The Mizar article:

On the Simple Closed Curve Property of the Circle and the Fashoda Meet Theorem for It

by
Yatsuka Nakamura

Received August 20, 2001

Copyright (c) 2001 Association of Mizar Users

MML identifier: JGRAPH_3
[ MML identifier index ]


environ

 vocabulary ARYTM, SQUARE_1, EUCLID, PCOMPS_1, RELAT_1, FUNCT_5, PRE_TOPC,
      MCART_1, ARYTM_1, ARYTM_3, RCOMP_1, COMPLEX1, FUNCT_1, BOOLE, SUBSET_1,
      COMPTS_1, ORDINAL2, TOPMETR, JORDAN2C, FUNCT_4, PARTFUN1, METRIC_1,
      TOPS_2, TOPREAL2, TOPREAL1, BORSUK_1, JGRAPH_3, SEQ_1;
 notation TARSKI, XBOOLE_0, SUBSET_1, ORDINAL1, NUMBERS, XCMPLX_0, XREAL_0,
      REAL_1, EUCLID, RELAT_1, TOPS_2, FUNCT_1, STRUCT_0, PARTFUN1, TOPREAL1,
      TOPMETR, PCOMPS_1, COMPTS_1, METRIC_1, RCOMP_1, SQUARE_1, FUNCT_2,
      PSCOMP_1, PRE_TOPC, JGRAPH_1, JORDAN2C, FUNCT_4, WELLFND1, TOPREAL2,
      TOPGRP_1;
 constructors REAL_1, GOBOARD5, TOPS_2, RCOMP_1, PSCOMP_1, JORDAN2C, COMPTS_1,
      TOPREAL2, TOPGRP_1, CONNSP_1, TOPMETR, WELLFND1, TOPRNS_1;
 clusters XREAL_0, STRUCT_0, RELSET_1, FUNCT_1, EUCLID, PRE_TOPC, SQUARE_1,
      BORSUK_1, TOPREAL2, TOPREAL6, BORSUK_2, BORSUK_3, MEMBERED;
 requirements REAL, NUMERALS, BOOLE, SUBSET, ARITHM;
 definitions TARSKI, FUNCT_1, XBOOLE_0;
 theorems TARSKI, AXIOMS, RELAT_1, SUBSET_1, FUNCT_1, FUNCT_2, FUNCT_4, TOPS_1,
      TOPS_2, PARTFUN1, PRE_TOPC, REVROT_1, FRECHET, TOPMETR, JORDAN6, EUCLID,
      RELSET_1, REAL_1, REAL_2, JGRAPH_1, SEQ_2, SQUARE_1, TOPREAL3, PSCOMP_1,
      METRIC_1, SPPOL_2, JGRAPH_2, RCOMP_1, COMPTS_1, ZFMISC_1, GOBOARD6,
      TOPGRP_1, TOPREAL1, TOPREAL2, RFUNCT_2, COMPLEX1, JORDAN1, XBOOLE_0,
      XBOOLE_1, XREAL_0, TOPRNS_1, XCMPLX_0, XCMPLX_1;
 schemes FUNCT_1, FUNCT_2, DOMAIN_1, JGRAPH_2;

begin ::Preliminaries

reserve x,y,z,u,a for real number;

Lm1: x^2+1 > 0
proof
    x^2 >= 0 by SQUARE_1:72;
  then x^2+1 >= 0+1 by REAL_1:55;
  hence thesis by AXIOMS:22;
end;

Lm2:TOP-REAL 2=TopSpaceMetr(Euclid 2) by EUCLID:def 8;
Lm3:dom proj1=the carrier of TOP-REAL 2 &
   dom proj2=the carrier of TOP-REAL 2 by FUNCT_2:def 1;

theorem Th1: x^2=y^2 implies x=y or x=-y
 proof assume x^2=y^2; then x^2-y^2=0 by XCMPLX_1:14;
   then (x-y)*(x+y)=0 by SQUARE_1:67;
   then x-y=0 or x+y=0 by XCMPLX_1:6;
   then x=y or x=0-y by XCMPLX_1:15,26;
  hence x=y or x=-y by XCMPLX_1:150;
 end;

theorem Th2: x^2=1 implies x=1 or x=-1
 proof assume x^2=1;
   then x^2-1^2=0 by SQUARE_1:59;
   then (x-1)*(x+1)=0 by SQUARE_1:67;
   then x-1=0 or x+1=0 by XCMPLX_1:6;
   then x-1+1=1 or x+1-1=0-1;
  hence x=1 or x=-1 by XCMPLX_1:26,27;
 end;

theorem Th3: 0<=x & x<=1 implies x^2<=x
 proof assume A1:0<=x & x<=1;
   per cases by A1;
   suppose 0=x; hence x^2<=x by SQUARE_1:60;
   suppose A2:0<x;
       now per cases by A1,REAL_1:def 5;
     case x=1; hence x^2<=x by SQUARE_1:59;
     case x<1; hence x^2<=x by A2,SQUARE_1:75;
     end;
    hence x^2<=x;
 end;

theorem Th4: a>=0 & (x-a)*(x+a)<=0 implies -a<=x & x<=a
 proof assume A1:a>=0 & (x-a)*(x+a)<=0;
   then A2:x-a>=0 & x+a<=0 or x-a<=0 & x+a>=0 by REAL_2:129;
   x+0<=x+a by A1,REAL_1:55;
   then x-a<=x+a-a by REAL_1:49;
   then x-a<=x by XCMPLX_1:26;
   then x<=a+0 & x+a>=0 by A1,A2,REAL_1:86;
   then x<=a & x>=0-a by REAL_1:86;
  hence -a<=x & x<=a by XCMPLX_1:150;
 end;

theorem Th5:
x^2-1<=0 implies -1<=x & x<=1
 proof assume x^2-1<=0;
  then 1>=0 & (x-1)*(x+1)<=0 by SQUARE_1:59,67;
  hence thesis by Th4;
 end;

theorem Th6:
 x < y & x < z iff x < min(y,z)
 proof
  thus x < y & x < z implies x < min(y,z) by SQUARE_1:38;
  assume A1:x < min(y,z);
    y>=min(y,z) & z>=min(y,z) by SQUARE_1:35;
  hence thesis by A1,AXIOMS:22;
 end;

theorem Th7:0<x implies x/3<x & x/4<x
  proof
   assume A1:0<x;
   then A2: 0<x/3 by SEQ_2:6;
   then A3:0+x/3<x/3+x/3 by REAL_1:53;
     x/3+x/3+0<x/3+x/3+x/3 by A2,REAL_1:53;
   then x/3+x/3<x by XCMPLX_1:69;
   hence x/3<x by A3,AXIOMS:22;
   A4: 0<x/4 by A1,SEQ_2:6;
   then A5:0+x/4<x/4+x/4 by REAL_1:53;
     x/4+x/4+0<x/4+x/4+x/4 by A4,REAL_1:53;
   then x/4< x/4+x/4+x/4 by A5,AXIOMS:22;
   then x/4+x/4<x/4+x/4+x/4+x/4 by REAL_1:53;
   then x/4+x/4< x by XCMPLX_1:71;
   hence x/4<x by A5,AXIOMS:22;
  end;

theorem Th8: (x>=1 implies sqrt x>=1) & (x>1 implies sqrt x>1)
proof
 hereby assume x>=1; hence sqrt x>=1 by SQUARE_1:83,94;
 end;
 assume x>1; hence sqrt x>1 by SQUARE_1:83,95;
end;

theorem Th9: x<=y & z<=u implies ].y,z.[ c= ].x,u.[
proof assume A1:x<=y & z<=u;
 let a be set;assume a in ].y,z.[;
   then a in {b where b is Real: y<b & b<z} by RCOMP_1:def 2;
   then consider b being Real such that A2:b=a & y<b & b<z;
     x<b & b<u by A1,A2,AXIOMS:22;
  hence a in ].x,u.[ by A2,JORDAN6:45;
end;

theorem for p being Point of TOP-REAL 2 holds
 |.p.| = sqrt((p`1)^2+(p`2)^2) &
 |.p.|^2 = (p`1)^2+(p`2)^2 by JGRAPH_1:46,47;

theorem for f being Function,B,C being set holds (f|B).:C = f.:(C /\ B)
 proof let f be Function,B,C be set;
   thus (f|B).:C c=f.:(C /\ B)
    proof let x be set;assume x in (f|B).:C;
      then consider y being set such that
      A1: y in dom (f|B) & y in C & x=(f|B).y by FUNCT_1:def 12;
         dom (f|B)=(dom f)/\ B by FUNCT_1:68;
       then A2:y in dom f & y in B by A1,XBOOLE_0:def 3;
       then A3:y in C /\ B by A1,XBOOLE_0:def 3;
         (f|B).y=f.y by A1,FUNCT_1:68;
     hence thesis by A1,A2,A3,FUNCT_1:def 12;
    end;
    let x be set;assume x in f.:(C /\ B);
      then consider y being set such that
      A4: y in dom f & y in C /\ B & x=f.y by FUNCT_1:def 12;
      A5: y in C & y in B by A4,XBOOLE_0:def 3;
      then y in (dom f)/\ B by A4,XBOOLE_0:def 3;
      then A6:y in dom (f|B) by FUNCT_1:68;
      then (f|B).y=f.y by FUNCT_1:68;
     hence thesis by A4,A5,A6,FUNCT_1:def 12;
 end;

theorem Th12: for X being TopStruct,Y being non empty TopStruct,
 f being map of X,Y,
 P being Subset of X holds f|P is map of X|P,Y
proof let X be TopStruct,Y be non empty TopStruct,f be map of X,Y,
  P be Subset of X;
  set Q=P;
    Q = the carrier of (X|Q) by JORDAN1:1;
  then f|P is Function of the carrier of (X|P),the carrier of Y by FUNCT_2:38;
 hence thesis ;
end;

theorem Th13:for X,Y being non empty TopSpace,
  p0 being Point of X,
  D being non empty Subset of X,
  E being non empty Subset of Y,
  f being map of X,Y
 st D`={p0} & E`={f.p0} & X is_T2 & Y is_T2 &
 (for p being Point of X|D holds f.p<>f.p0)&
 (ex h being map of X|D,Y|E st h=f|D & h is continuous) &
 (for V being Subset of Y st f.p0 in V & V is open
 ex W being Subset of X st p0 in W & W is open & f.:W c= V)
 holds f is continuous
 proof let X,Y be non empty TopSpace,
  p0 be Point of X,
  D be non empty Subset of X,
  E be non empty Subset of Y,
  f be map of X,Y;
  assume A1:D`={p0} & E`={f.p0} & X is_T2 & Y is_T2 &
   (for p being Point of X|D holds f.p<>f.p0)&
   (ex h being map of X|D,Y|E st h=f|D & h is continuous) &
   (for V being Subset of Y st f.p0 in V & V is open
     ex W being Subset of X st p0 in W & W is open & f.:W c= V);
     for p being Point of X,V being Subset of Y
      st f.p in V & V is open holds
      ex W being Subset of X st p in W & W is open & f.:W c= V
    proof let p be Point of X,V be Subset of Y;
     assume A2:f.p in V & V is open;
      A3:the carrier of X|D=D by JORDAN1:1;
      per cases;
      suppose p=p0;
       hence thesis by A1,A2;
      suppose A4:p<>p0;
        then not p in D` by A1,TARSKI:def 1;
        then p in (the carrier of X)\D` by XBOOLE_0:def 4;
then A5:     p in D`` by SUBSET_1:def 5;
        then f.p<>f.p0 by A1,A3;
        then consider G1,G2 being Subset of Y such that
        A6: G1 is open & G2 is open &
        f.p in G1 & f.p0 in G2 & G1 misses G2 by A1,COMPTS_1:def 4;
        consider h being map of X|D,Y|E such that
        A7: h=f|D & h is continuous by A1;
        A8:[#](X|D)=D by PRE_TOPC:def 10;
        then reconsider p22=p as Point of X|D by A5;
        A9:the carrier of Y|E=[#](Y|E) by PRE_TOPC:12;
        A10:[#](Y|E)=E by PRE_TOPC:def 10;
        then (G1 /\ V) /\ E c= the carrier of Y|E by A9,XBOOLE_1:17;
        then reconsider V20=(G1 /\ V) /\ E as Subset of Y|E;
        A11:h.p=f.p by A5,A7,FUNCT_1:72;
          f.p<>f.p0 by A1,A5,A8;
        then not f.p in E` by A1,TARSKI:def 1;
        then not f.p in (the carrier of Y) \E by SUBSET_1:def 5;
        then A12:h.p22 in E by A11,XBOOLE_0:def 4;
          h.p22 in G1 /\ V by A2,A6,A11,XBOOLE_0:def 3;
        then A13:h.p22 in V20 by A12,XBOOLE_0:def 3;
          G1 /\ V is open by A2,A6,TOPS_1:38;
        then V20 is open by A10,TOPS_2:32;
        then consider W2 being Subset of X|D such that
        A14:p22 in W2 & W2 is open & h.:W2 c= V20 by A7,A13,JGRAPH_2:20;
        consider W3b being Subset of X such that
        A15: W3b is open & W2=W3b /\ D by A8,A14,TOPS_2:32;
        A16:p22 in W3b by A14,A15,XBOOLE_0:def 3;
        consider H1,H2 being Subset of X such that
        A17: H1 is open & H2 is open &
        p in H1 & p0 in H2 & H1 misses H2 by A1,A4,COMPTS_1:def 4;
        A18:H1 /\ W3b is open by A15,A17,TOPS_1:38;
        A19:p in H1 /\ W3b by A16,A17,XBOOLE_0:def 3;
        reconsider W3=H1 /\ W3b as Subset of X;
        A20:W3 c= W3b by XBOOLE_1:17;
        A21:f.:W3 c= h.:W2
         proof let xx be set;assume xx in f.:W3;
           then consider yy being set such that
           A22: yy in dom f & yy in W3 & xx=f.yy by FUNCT_1:def 12;
           A23:dom h=dom f /\ D by A7,FUNCT_1:68;
           A24:W3 c= H1 by XBOOLE_1:17;
             H2 c= H1` by A17,SUBSET_1:43;
           then D` c= H1` by A1,A17,ZFMISC_1:37;
           then H1 c= D by SUBSET_1:31;
           then A25:W3 c= D by A24,XBOOLE_1:1;
           then A26:yy in dom h by A22,A23,XBOOLE_0:def 3;
           then A27:h.yy=f.yy by A7,FUNCT_1:70;
             yy in W2 by A15,A20,A22,A25,XBOOLE_0:def 3;
          hence xx in h.:W2 by A22,A26,A27,FUNCT_1:def 12;
         end;
       A28:(G1 /\ V) /\ E c= G1 /\ V by XBOOLE_1:17;
       A29:G1 /\ V c= V by XBOOLE_1:17;
         h.:W2 c= G1 /\ V by A14,A28,XBOOLE_1:1;
       then h.:W2 c= V by A29,XBOOLE_1:1;
       then f.:W3 c= V by A21,XBOOLE_1:1;
       hence thesis by A18,A19;
    end;
  hence thesis by JGRAPH_2:20;
 end;

begin ::The Circle is a Simple Closed Curve

reserve p,q for Point of TOP-REAL 2;

definition
  func Sq_Circ -> Function of the carrier of TOP-REAL 2,
                              the carrier of TOP-REAL 2 means :Def1:
  for p being Point of TOP-REAL 2 holds
  (p=0.REAL 2 implies it.p=p) &
  ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
  it.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
  (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
  it.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|);
existence
  proof
   set BP= the carrier of TOP-REAL 2;
   defpred P[set,set] means
     (for p being Point of TOP-REAL 2 st p=$1 holds
   (p=0.REAL 2 implies $2=p)&
   ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   $2=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
   (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   $2=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|));
  A1:for x being Element of BP ex y being Element of BP st P[x,y]
proof let x be Element of BP;
  set q=x;
  per cases;
  suppose q=0.REAL 2;
   then for p being Point of TOP-REAL 2 st p=x holds
   (p=0.REAL 2 implies 0.REAL 2=p)&
   ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   0.REAL 2=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
   (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   0.REAL 2=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|);
   hence thesis;
  suppose A2:(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1) & q<>0.REAL 2;
   set r= |[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|;
     for p being Point of TOP-REAL 2 st p=x holds
    (p=0.REAL 2 implies r=p)&
    ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
    r=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
    (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
    r=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|) by A2;
   hence thesis;
  suppose A3:not (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1) & q<>0.REAL 2;
   set r= |[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|;
     for p being Point of TOP-REAL 2 st p=x holds
   (p=0.REAL 2 implies r=p)&
   ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   r=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
   (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   r=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|) by A3;
   hence thesis;
end;
     ex h being Function of BP, BP st for x being Element of BP holds
P[x,h.x] from FuncExD(A1);
   then consider h being Function of BP,BP such that
A4: for x being Element of BP holds
  for p being Point of TOP-REAL 2 st p=x holds
   (p=0.REAL 2 implies h.x=p)&
   ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h.x=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
   (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h.x=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|);
    for p being Point of TOP-REAL 2 holds
   (p=0.REAL 2 implies h.p=p)&
   ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
   (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|) by A4;
   hence thesis;
  end;
uniqueness
  proof
  let h1,h2 be Function of the carrier of TOP-REAL 2,
      the carrier of TOP-REAL 2;
assume A5:(for p being Point of TOP-REAL 2 holds
   (p=0.REAL 2 implies h1.p=p)&
   ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h1.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
   (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h1.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|))&
  (for p being Point of TOP-REAL 2 holds
   (p=0.REAL 2 implies h2.p=p)&
   ((p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h2.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)&
   (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
   h2.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|));
    for x being set st x in (the carrier of TOP-REAL 2) holds h1.x=h2.x
  proof let x be set;
   assume x in the carrier of TOP-REAL 2;
   then reconsider q=x as Point of TOP-REAL 2;
   per cases;
   suppose A6:q=0.REAL 2;
   then h1.q=q by A5;
   hence h1.x=h2.x by A5,A6;
   suppose A7:(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1)& q<>0.REAL 2;
   then h1.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]| by A5;
   hence h1.x=h2.x by A5,A7;
   suppose A8:not (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1)
      & q<>0.REAL 2;
    then h1.q=|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]| by A5;
   hence h1.x=h2.x by A5,A8;
  end;
hence h1=h2 by FUNCT_2:18;
  end;
end;

theorem Th14: for p being Point of TOP-REAL 2 st p<>0.REAL 2 holds
 ((p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)implies
 Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|) &
 (not(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) implies
 Sq_Circ.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)
proof let p be Point of TOP-REAL 2;assume
   A1: p<>0.REAL 2;
     hereby assume A2:p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2;
         now per cases by A2;
       case A3:p`1<=p`2 & -p`2<=p`1;
          now assume A4:p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1;
          A5: now per cases by A4;
           case p`2<=p`1 & -p`1<=p`2;
             hence p`1=p`2 or p`1=-p`2 by A3,AXIOMS:21;
           case p`2>=p`1 & p`2<=-p`1; then -p`2>=--p`1 by REAL_1:50;
            hence p`1=p`2 or p`1=-p`2 by A3,AXIOMS:21;
           end;
             now per cases by A5;
           case p`1=p`2;
            hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)
]|
                                       by A1,A4,Def1;
           case A6:p`1=-p`2;
             A7:now assume A8:p`1=0;
               then p`2=-0 by A6 .=0;
              hence contradiction by A1,A8,EUCLID:57,58;
             end;
             A9:-p`1=p`2 by A6;
               p`2<>0 by A6,A7;
             then p`1/p`2=-1 by A6,XCMPLX_1:198;
             then A10:(p`1/p`2)^2=1^2 by SQUARE_1:61;
               p`2/p`1=-1 by A7,A9,XCMPLX_1:198;
           then (p`2/p`1)^2=1^2 by SQUARE_1:61;
          hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|
                                             by A1,A4,A10,Def1;
          end;
        hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|;
        end;
       hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|
                                             by A1,Def1;
       case A11:p`1>=p`2 & p`1<=-p`2;
          now assume A12:p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1;
        A13: now per cases by A12;
         case p`2<=p`1 & -p`1<=p`2; then --p`1>=-p`2 by REAL_1:50;
           hence p`1=p`2 or p`1=-p`2 by A11,AXIOMS:21;
         case p`2>=p`1 & p`2<=-p`1;
           hence p`1=p`2 or p`1=-p`2 by A11,AXIOMS:21;
         end;
          now per cases by A13;
        case p`1=p`2;
         hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|
                                     by A1,A12,Def1;
        case A14:p`1=-p`2;
         A15:now assume A16:p`1=0;
          then p`2=-0 by A14 .=0;
          hence contradiction by A1,A16,EUCLID:57,58;
         end;
         A17:-p`1=p`2 by A14;
           p`2<>0 by A14,A15;
         then p`1/p`2=-1 by A14,XCMPLX_1:198;
         then A18:(p`1/p`2)^2=1^2 by SQUARE_1:61;
           p`2/p`1=-1 by A15,A17,XCMPLX_1:198;
         then (p`2/p`1)^2=1^2 by SQUARE_1:61;
         hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|
                                        by A1,A12,A18,Def1;
        end;
        hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|;
        end;
        hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|
                                               by A1,Def1;
       end;
      hence Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|;
     end;
     assume A19:not(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2);
     A20:-p`2<p`1 implies --p`2>-p`1 by REAL_1:50;
       -p`2>p`1 implies --p`2<-p`1 by REAL_1:50;
     hence thesis by A1,A19,A20,Def1;
end;

theorem Th15: for X being non empty TopSpace,
f1 being map of X,R^1 st f1 is continuous &
(for q being Point of X ex r being real number st f1.q=r & r>=0)
 holds ex g being map of X,R^1
st (for p being Point of X,r1 being real number st
f1.p=r1 holds g.p=sqrt(r1)) & g is continuous
proof let X being non empty TopSpace,f1 be map of X,R^1;
assume A1: f1 is continuous &
(for q being Point of X ex r being real number st f1.q=r & r>=0);
defpred P[set,set] means
 (for r11 being real number st f1.$1=r11 holds $2=sqrt(r11));
  A2:for x being Element of X
  ex y being Element of REAL st P[x,y]
  proof let x be Element of X;
    reconsider pp=x as Point of X;
    reconsider r1=f1.pp as Real by TOPMETR:24;
      for r11 being real number st f1.x=r11 holds sqrt(r1)=sqrt(r11);
   hence thesis;
  end;
    ex f being Function of the carrier of X,REAL
  st for x2 being Element of X holds P[x2,f.x2]
 from FuncExD(A2);
  then consider f being Function of the carrier of X,REAL
  such that A3:  for x2 being Element of X holds
  (for r11 being real number st f1.x2=r11 holds f.x2=sqrt(r11));
  reconsider g0=f as map of X,R^1 by TOPMETR:24;
  A4: for p being Point of X,r11 being real number st
  f1.p=r11 holds g0.p=sqrt(r11) by A3;
    for p being Point of X,V being Subset of R^1
   st g0.p in V & V is open holds
   ex W being Subset of X st p in W & W is open & g0.:W c= V
    proof let p be Point of X,V be Subset of R^1;
     assume A5:g0.p in V & V is open;
      reconsider r=g0.p as Real by TOPMETR:24;
      reconsider r1=f1.p as Real by TOPMETR:24;
      consider r8 being real number such that
      A6: f1.p=r8 & r8>=0 by A1;
      A7: r=sqrt(r1) by A3;
      then A8:r>=0 by A6,SQUARE_1:82,94;
      consider r01 being Real such that
      A9: r01>0 & ].r-r01,r+r01.[ c= V by A5,FRECHET:8;
      set r0=min(r01,1);
      A10:r0>0 by A9,Th6;
      A11:r1=r^2 by A6,A7,SQUARE_1:def 4;
       A12: r+r0>=r+0 by A10,REAL_1:55;
        r0<=r01 by SQUARE_1:35;
      then r-r01<=r-r0 & r+r0<=r+r01 by REAL_1:55,REAL_2:106;
      then ].r-r0,r+r0.[ c= ].r-r01,r+r01.[ by Th9;
      then A13: r0>0 & ].r-r0,r+r0.[ c= V by A9,Th6,XBOOLE_1:1;
      then A14:r0^2>0 by SQUARE_1:74;
        2*r>=0 by A8,REAL_2:121;
      then 2*r*r0>=0 by A13,REAL_2:121;
      then A15:2*r*r0+r0^2>0+0 by A14,REAL_1:67;
      A16:(r-r0)^2>=0 by SQUARE_1:72;
     per cases;
     suppose A17: r-r0>0;
        now assume r1=0; then r=0 by A3,SQUARE_1:82;
        then -r0>0 by A17,XCMPLX_1:150;
       hence contradiction by A10,REAL_1:66;
      end;
      then A18:0<r by A6,A7,SQUARE_1:93;
      set r4=r0*(r-r0);
      A19:r4>0 by A13,A17,REAL_2:122;
      then A20:r1+r4>0+0 by A6,REAL_1:67;
        r0*r0>0 by A13,REAL_2:122;
      then A21:2*(r0*r0)>0 by REAL_2:122;
      A22:r0*r>0 by A13,A18,REAL_2:122;
      then 0+r*r0< r*r0+r*r0 by REAL_1:67;
      then r0*r< 2*(r*r0) by XCMPLX_1:11;
      then r0*r< 2*r*r0 by XCMPLX_1:4;
      then r0*r+0< 2*r*r0+2*(r0*r0) by A21,REAL_1:67;
      then r0*r< 2*r*r0+(r0*r0+r0*r0) by XCMPLX_1:11;
      then r0*r< 2*r*r0+r0*r0+r0*r0 by XCMPLX_1:1;
      then r0*r-r0*r0+r0*r0< 2*r*r0+r0*r0+r0*r0 by XCMPLX_1:27;
      then r0*r-r0*r0< 2*r*r0+r0*r0 by REAL_1:55;
      then r4 <2*r*r0+r0*r0 by XCMPLX_1:40;
      then r4 <2*r*r0+r0^2 by SQUARE_1:def 3;
      then r1+r4 <r^2+(2*r*r0+r0^2) by A11,REAL_1:67;
      then r1+r4 <r^2+2*r*r0+r0^2 by XCMPLX_1:1;
      then r1+r4 <(r+r0)^2 by SQUARE_1:63;
      then sqrt(r1+r4)<sqrt((r+r0)^2) by A20,SQUARE_1:95;
      then A23:r+r0>sqrt(r1+r4) by A8,A12,SQUARE_1:89;
        0+r*r0< r*r0+r*r0 by A22,REAL_1:67;
      then r0*r< 2*(r*r0) by XCMPLX_1:11;
      then r0*r< 2*r*r0 by XCMPLX_1:4;
      then r0*r-r0*r0< 2*r*r0-r0*r0 by REAL_1:92;
      then r4 <2*r*r0-r0*r0 by XCMPLX_1:40;
      then r4 <2*r*r0-r0^2 by SQUARE_1:def 3;
      then -r4 >-(2*r*r0-r0^2) by REAL_1:50;
      then r1+-r4 >r^2+-(2*r*r0-r0^2) by A11,REAL_1:67;
      then r1-r4 >r^2+-(2*r*r0-r0^2) by XCMPLX_0:def 8;
      then r1-r4 >r^2-(2*r*r0-r0^2) by XCMPLX_0:def 8;
      then r1-r4 >r^2-2*r*r0+r0^2 by XCMPLX_1:37;
      then r1-r4 >(r-r0)^2 by SQUARE_1:64;
      then sqrt(r1-r4)>sqrt((r-r0)^2) by A16,SQUARE_1:95;
      then A24:sqrt(r1-r4)>r-r0 by A17,SQUARE_1:89;
       4=2*2 .= 2^2 by SQUARE_1:def 3;
      then A25:1/4=(1/2)^2 by SQUARE_1:59,69;
      A26:r1-r4=r^2-(r0*r-r0*r0)by A11,XCMPLX_1:40
      .=r^2-r0*r+r0*r0 by XCMPLX_1:37
      .=r^2-(2*(1/2))*r0*r+r0^2 by SQUARE_1:def 3
      .=r^2-2*((1/2)*r0)*r+(1/4+3/4)*r0^2 by XCMPLX_1:4
      .=r^2-2*((1/2)*r0)*r+((1/4)*r0^2+(3/4)*r0^2) by XCMPLX_1:8
      .=r^2-2*((1/2)*r0)*r+(1/4)*r0^2+(3/4)*r0^2 by XCMPLX_1:1
      .=r^2-2*((1/2)*r0)*r+((1/2)*r0)^2+(3/4)*r0^2 by A25,SQUARE_1:68
      .=r^2-2*r*((1/2)*r0)+((1/2)*r0)^2+(3/4)*r0^2 by XCMPLX_1:4
      .=(r-(1/2)*r0)^2+(3/4)*r0^2 by SQUARE_1:64;
      A27:(r-(1/2)*r0)^2>=0 by SQUARE_1:72;
        r0^2>=0 by SQUARE_1:72;
      then (3/4)*r0^2>=0 by REAL_2:121;
      then A28:r1-r4>=0+0 by A26,A27,REAL_1:55;
      reconsider G1=].r1-r4,r1+r4.[ as Subset of R^1
                          by TOPMETR:24;
      A29:r1<r1+r4 by A19,REAL_1:69;
      then r1-r4<r1 by REAL_1:84;
      then A30:f1.p in G1 by A29,JORDAN6:45;
        G1 is open by JORDAN6:46;
      then consider W1 being Subset of X such that
      A31: p in W1 & W1 is open & f1.:W1 c= G1 by A1,A30,JGRAPH_2:20;
      set W=W1;
        g0.:W c= ].r-r0,r+r0.[
       proof let x be set;assume x in g0.:W;
         then consider z being set such that
         A32: z in dom g0 & z in W & g0.z=x by FUNCT_1:def 12;
         reconsider pz=z as Point of X by A32;
           pz in the carrier of X;
         then pz in dom f1 by FUNCT_2:def 1;
         then A33:f1.pz in f1.:W1 by A32,FUNCT_1:def 12;
         reconsider aa1=f1.pz as Real by TOPMETR:24;
         consider r9 being real number such that A34:f1.pz=r9 & r9>=0 by A1;
         A35:x=sqrt(aa1) by A3,A32;
         A36:r1-r4<aa1 & aa1<r1+r4 by A31,A33,JORDAN6:45;
         then sqrt(aa1)<sqrt(r1+r4) by A34,SQUARE_1:95;
         then A37: sqrt(aa1)< r+r0 by A23,AXIOMS:22;
           now per cases;
         case 0<=r1-r4; then sqrt(r1-r4)<=sqrt(aa1) by A36,SQUARE_1:94;
          hence r-r0< sqrt(aa1) by A24,AXIOMS:22;
         case 0>r1-r4; hence contradiction by A28;
         end;
        hence x in ].r-r0,r+r0.[ by A35,A37,JORDAN6:45;
       end;
       then g0.:W c= V by A13,XBOOLE_1:1;
      hence thesis by A31;
     suppose A38:r-r0<=0;
      set r4=(2*r*r0+r0^2)/3;
      A39:(2*r*r0+r0^2)/3>0 by A15,REAL_2:127;
then A40: r1+r4>0+0 by A6,REAL_1:67;
        (2*r*r0+r0^2)/3<(2*r*r0+r0^2) by A15,Th7;
      then r1+r4 <r^2+(2*r*r0+r0^2) by A11,REAL_1:67;
      then r1+r4 <=r^2+2*r*r0+r0^2 by XCMPLX_1:1;
      then r1+r4 <=(r+r0)^2 by SQUARE_1:63;
      then sqrt(r1+r4)<=sqrt((r+r0)^2) by A40,SQUARE_1:94;
      then A41:r+r0>=sqrt(r1+r4) by A8,A12,SQUARE_1:89;
      reconsider G1=].r1-r4,r1+r4.[ as Subset of R^1
                          by TOPMETR:24;
      A42:r1<r1+r4 by A39,REAL_1:69;
      then r1-r4<r1 by REAL_1:84;
      then A43:f1.p in G1 by A42,JORDAN6:45;
        G1 is open by JORDAN6:46;
      then consider W1 being Subset of X such that
      A44: p in W1 & W1 is open & f1.:W1 c= G1 by A1,A43,JGRAPH_2:20;
      set W=W1;
        g0.:W c= ].r-r0,r+r0.[
       proof let x be set;assume x in g0.:W;
         then consider z being set such that
         A45: z in dom g0 & z in W & g0.z=x by FUNCT_1:def 12;
         reconsider pz=z as Point of X by A45;
           pz in the carrier of X;
         then pz in dom f1 by FUNCT_2:def 1;
         then A46:f1.pz in f1.:W1 by A45,FUNCT_1:def 12;
         reconsider aa1=f1.pz as Real by TOPMETR:24;
         consider r9 being real number such that A47:f1.pz=r9 & r9>=0 by A1;
         A48:x=sqrt(aa1) by A3,A45;
         A49:r1-r4<aa1 & aa1<r1+r4 by A44,A46,JORDAN6:45;
         then sqrt(aa1)<sqrt(r1+r4) by A47,SQUARE_1:95;
         then A50: sqrt(aa1)< r+r0 by A41,AXIOMS:22;
         A51:0<=sqrt(aa1) by A47,SQUARE_1:82,94;
           now per cases by A38;
         case A52:r-r0=0;
           then r=r0 by XCMPLX_1:15;
           then r4=(2*(r0*r0)+r0^2)/3 by XCMPLX_1:4
           .=(2*r0^2+r0^2)/3 by SQUARE_1:def 3
           .=(r0^2+r0^2+r0^2)/3 by XCMPLX_1:11
           .=r0^2 by XCMPLX_1:68;
           then r1-r4=(r-r0)*(r+r0) by A11,SQUARE_1:67 .=0 by A52;
          hence r-r0<sqrt(aa1) by A49,A52,SQUARE_1:82,95;
         case r-r0<0;
          hence r-r0<sqrt(aa1) by A51;
         end;
        hence x in ].r-r0,r+r0.[ by A48,A50,JORDAN6:45;
       end;
       then g0.:W c= V by A13,XBOOLE_1:1;
      hence thesis by A44;
      end;
     then g0 is continuous by JGRAPH_2:20;
 hence thesis by A4;
end;

theorem Th16: for X being non empty TopSpace,
f1,f2 being map of X,R^1 st f1 is continuous & f2 is continuous &
(for q being Point of X holds f2.q<>0)
holds ex g being map of X,R^1
st (for p being Point of X,r1,r2 being real number st
f1.p=r1 & f2.p=r2 holds g.p=(r1/r2)^2) & g is continuous
proof let X be non empty TopSpace,
f1,f2 be map of X,R^1;
assume f1 is continuous & f2 is continuous
& (for q being Point of X holds f2.q<>0);
  then consider g2 being map of X,R^1 such that
A1: (for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g2.p=r1/r2) & g2 is continuous by JGRAPH_2:37;
  consider g3 being map of X,R^1 such that
A2: (for p being Point of X,r1 being real number st
  g2.p=r1 holds g3.p=r1*r1) & g3 is continuous by A1,JGRAPH_2:32;
    for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g3.p=(r1/r2)^2
  proof let p be Point of X,r1,r2 be real number;
   assume f1.p=r1 & f2.p=r2;
    then g2.p=r1/r2 by A1;
    then g3.p=(r1/r2)*(r1/r2) by A2;
   hence thesis by SQUARE_1:def 3;
  end;
hence thesis by A2;
end;

theorem Th17: for X being non empty TopSpace,
f1,f2 being map of X,R^1 st f1 is continuous & f2 is continuous &
(for q being Point of X holds f2.q<>0)
holds ex g being map of X,R^1
st (for p being Point of X,r1,r2 being real number st
f1.p=r1 & f2.p=r2 holds g.p=1+(r1/r2)^2) & g is continuous
proof let X be non empty TopSpace,
f1,f2 be map of X,R^1;
assume f1 is continuous & f2 is continuous
& (for q being Point of X holds f2.q<>0);
then consider g2 being map of X,R^1
  such that A1: (for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g2.p=(r1/r2)^2) & g2 is continuous by Th16;
consider g3 being map of X,R^1 such that
A2: (for p being Point of X,r1 being real number st
  g2.p=r1 holds g3.p=r1+1) & g3 is continuous by A1,JGRAPH_2:34;
  for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g3.p=1+(r1/r2)^2
  proof let p be Point of X,r1,r2 be real number;
   assume f1.p=r1 & f2.p=r2;
    then g2.p=(r1/r2)^2 by A1;
   hence thesis by A2;
  end;
hence thesis by A2;
end;

theorem Th18: for X being non empty TopSpace,
f1,f2 being map of X,R^1 st f1 is continuous & f2 is continuous &
(for q being Point of X holds f2.q<>0)
holds ex g being map of X,R^1
st (for p being Point of X,r1,r2 being real number st
f1.p=r1 & f2.p=r2 holds g.p=sqrt(1+(r1/r2)^2)) & g is continuous
proof let X be non empty TopSpace,
f1,f2 be map of X,R^1;
assume f1 is continuous & f2 is continuous
& (for q being Point of X holds f2.q<>0);
then consider g2 being map of X,R^1
  such that A1: (for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g2.p=1+(r1/r2)^2) & g2 is continuous by Th17;
  for q being Point of X ex r being real number st g2.q=r & r>=0
  proof let q be Point of X;
    reconsider r1=f1.q,r2=f2.q as Real by TOPMETR:24;
    A2:g2.q=1+(r1/r2)^2 by A1;
      1+(r1/r2)^2>0 by Lm1;
   hence thesis by A2;
  end;
then consider g3 being map of X,R^1 such that
A3: (for p being Point of X,r1 being real number st
  g2.p=r1 holds g3.p=sqrt(r1)) & g3 is continuous by A1,Th15;
  for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g3.p=sqrt(1+(r1/r2)^2)
  proof let p be Point of X,r1,r2 be real number;
   assume f1.p=r1 & f2.p=r2;
    then g2.p=1+(r1/r2)^2 by A1;
   hence thesis by A3;
  end;
hence thesis by A3;
end;

theorem Th19: for X being non empty TopSpace,
f1,f2 being map of X,R^1 st f1 is continuous & f2 is continuous &
(for q being Point of X holds f2.q<>0)
holds ex g being map of X,R^1
st (for p being Point of X,r1,r2 being real number st
f1.p=r1 & f2.p=r2 holds g.p=r1/sqrt(1+(r1/r2)^2)) & g is continuous
proof let X be non empty TopSpace,f1,f2 be map of X,R^1;
assume A1:f1 is continuous & f2 is continuous
& (for q being Point of X holds f2.q<>0);
then consider g2 being map of X,R^1
  such that A2: (for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g2.p=sqrt(1+(r1/r2)^2)) & g2 is continuous
           by Th18;
  for q being Point of X holds g2.q<>0
  proof let q be Point of X;
    reconsider r1=f1.q,r2=f2.q as Real by TOPMETR:24;
      1+(r1/r2)^2>0 by Lm1;
    then sqrt(1+(r1/r2)^2)>0 by SQUARE_1:93;
   hence thesis by A2;
  end;
then consider g3 being map of X,R^1 such that
A3: (for p being Point of X,r1,r0 being real number st
  f1.p=r1 & g2.p=r0 holds g3.p=r1/r0) & g3 is continuous
   by A1,A2,JGRAPH_2:37;
  for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g3.p=r1/sqrt(1+(r1/r2)^2)
  proof let p be Point of X,r1,r2 be real number;
   assume A4:f1.p=r1 & f2.p=r2;
    then g2.p=sqrt(1+(r1/r2)^2) by A2;
   hence thesis by A3,A4;
  end;
hence thesis by A3;
end;

theorem Th20: for X being non empty TopSpace,
f1,f2 being map of X,R^1 st f1 is continuous & f2 is continuous &
(for q being Point of X holds f2.q<>0)
holds ex g being map of X,R^1
st (for p being Point of X,r1,r2 being real number st
f1.p=r1 & f2.p=r2 holds g.p=r2/sqrt(1+(r1/r2)^2)) & g is continuous
proof let X be non empty TopSpace,
f1,f2 be map of X,R^1;
assume A1:f1 is continuous & f2 is continuous
& (for q being Point of X holds f2.q<>0);
then consider g2 being map of X,R^1
  such that A2: (for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g2.p=sqrt(1+(r1/r2)^2)) & g2 is continuous
           by Th18;
  for q being Point of X holds g2.q<>0
  proof let q be Point of X;
    reconsider r1=f1.q,r2=f2.q as Real by TOPMETR:24;
      1+(r1/r2)^2>0 by Lm1;
    then sqrt(1+(r1/r2)^2)>0 by SQUARE_1:93;
   hence thesis by A2;
  end;
then consider g3 being map of X,R^1
  such that A3: (for p being Point of X,r2,r0 being real number st
  f2.p=r2 & g2.p=r0 holds g3.p=r2/r0) & g3 is continuous
                          by A1,A2,JGRAPH_2:37;
  for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g3.p=r2/sqrt(1+(r1/r2)^2)
  proof let p be Point of X,r1,r2 be real number;
   assume A4:f1.p=r1 & f2.p=r2;
    then g2.p=sqrt(1+(r1/r2)^2) by A2;
   hence thesis by A3,A4;
  end;
hence thesis by A3;
end;

Lm4: for K1 being non empty Subset of TOP-REAL 2 holds
  for q being Point of (TOP-REAL 2)|K1 holds (proj2|K1).q=proj2.q
proof
  let K1 be non empty Subset of TOP-REAL 2;
  let q be Point of (TOP-REAL 2)|K1;
  A1: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
    q in the carrier of (TOP-REAL 2)|K1;
  then q in dom proj2 /\ K1 by A1,Lm3,XBOOLE_0:def 3;
  hence thesis by FUNCT_1:71;
end;

Lm5: for K1 being non empty Subset of TOP-REAL 2 holds
  proj2|K1 is continuous map of (TOP-REAL 2)|K1,R^1
proof
 let K1 be non empty Subset of TOP-REAL 2;
A1: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
    proj2|K1 is Function of K1,the carrier of R^1 by FUNCT_2:38,TOPMETR:24;
  then reconsider g2=proj2|K1 as map of (TOP-REAL 2)|K1,R^1 by A1;
    for q be Point of (TOP-REAL 2)|K1 holds g2.q=proj2.q by Lm4;
  hence thesis by JGRAPH_2:40;
end;

Lm6: for K1 being non empty Subset of TOP-REAL 2 holds
  for q being Point of (TOP-REAL 2)|K1 holds (proj1|K1).q=proj1.q
proof
  let K1 be non empty Subset of TOP-REAL 2;
  let q be Point of (TOP-REAL 2)|K1;
  A1: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
    q in the carrier of (TOP-REAL 2)|K1;
  then q in dom proj1 /\ K1 by A1,Lm3,XBOOLE_0:def 3;
  hence thesis by FUNCT_1:71;
end;

Lm7: for K1 being non empty Subset of TOP-REAL 2 holds
  proj1|K1 is continuous map of (TOP-REAL 2)|K1,R^1
proof
 let K1 be non empty Subset of TOP-REAL 2;
A1: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
    proj1|K1 is Function of K1,the carrier of R^1 by FUNCT_2:38,TOPMETR:24;
  then reconsider g2=proj1|K1 as map of (TOP-REAL 2)|K1,R^1 by A1;
    for q be Point of (TOP-REAL 2)|K1 holds g2.q=proj1.q by Lm6;
  hence thesis by JGRAPH_2:39;
end;

theorem Th21: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1/sqrt(1+(p`2/p`1)^2)) & (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0 ) holds
f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of (TOP-REAL 2) st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1/sqrt(1+(p`2/p`1)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    now let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g1.q=proj1.q by Lm6 .=q2`1 by PSCOMP_1:def 28;
   hence g1.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g2.q=r1 & g1.q=r2
  holds g3.q=r2/sqrt(1+(r1/r2)^2)) & g3 is continuous by Th20;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
    for x being set st x in dom f holds f.x=g3.x
   proof let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`1/sqrt(1+(r`2/r`1)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence thesis by A3,A4,FUNCT_1:9;
end;

theorem Th22: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2/sqrt(1+(p`2/p`1)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0 ) holds
f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2/sqrt(1+(p`2/p`1)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    now let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g1.q=proj1.q by Lm6 .=q2`1 by PSCOMP_1:def 28;
   hence g1.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g2.q=r1 & g1.q=r2
  holds g3.q=r1/sqrt(1+(r1/r2)^2)) & g3 is continuous by Th19;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
    for x being set st x in dom f holds f.x=g3.x
   proof let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`2/sqrt(1+(r`2/r`1)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence f is continuous by A3,A4,FUNCT_1:9;
end;

theorem Th23: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2/sqrt(1+(p`1/p`2)^2)) & (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0 ) holds
f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2/sqrt(1+(p`1/p`2)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    now let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g2.q=proj2.q by Lm4 .=q2`2 by PSCOMP_1:def 29;
   hence g2.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g1.q=r1 & g2.q=r2
  holds g3.q=r2/sqrt(1+(r1/r2)^2)) & g3 is continuous by Th20;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
    for x being set st x in dom f holds f.x=g3.x
   proof let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`2/sqrt(1+(r`1/r`2)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence f is continuous by A3,A4,FUNCT_1:9;
end;

theorem Th24: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1/sqrt(1+(p`1/p`2)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0 ) holds
f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1/sqrt(1+(p`1/p`2)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    now let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g2.q=proj2.q by Lm4 .=q2`2 by PSCOMP_1:def 29;
   hence g2.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g1.q=r1 & g2.q=r2
  holds g3.q=r1/sqrt(1+(r1/r2)^2)) & g3 is continuous by Th19;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
    for x being set st x in dom f holds f.x=g3.x
   proof let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`1/sqrt(1+(r`1/r`2)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence f is continuous by A3,A4,FUNCT_1:9;
end;

Lm8: ((1.REAL 2)`2<=(1.REAL 2)`1 & -(1.REAL 2)`1<=(1.REAL 2)`2 or
      (1.REAL 2)`2>=(1.REAL 2)`1 & (1.REAL 2)`2<=-(1.REAL 2)`1) &
      (1.REAL 2)<>0.REAL 2 by JGRAPH_2:13,REVROT_1:19;

Lm9:for K1 being non empty Subset of TOP-REAL 2 holds
  dom ((proj2)*(Sq_Circ|K1)) = the carrier of (TOP-REAL 2)|K1
proof
 let K1 be non empty Subset of TOP-REAL 2;
A1:dom ((proj2)*(Sq_Circ|K1)) c= dom (Sq_Circ|K1) by RELAT_1:44;
 dom (Sq_Circ|K1) c= dom ((proj2)*(Sq_Circ|K1))
proof let x be set;assume A2:x in dom (Sq_Circ|K1);
   then A3:x in dom Sq_Circ /\ K1 by FUNCT_1:68;
   A4:(Sq_Circ|K1).x=Sq_Circ.x by A2,FUNCT_1:68;
     x in dom Sq_Circ by A3,XBOOLE_0:def 3;
   then Sq_Circ.x in rng Sq_Circ by FUNCT_1:12;
  hence x in dom ((proj2)*(Sq_Circ|K1)) by A2,A4,Lm3,FUNCT_1:21;
end;
hence dom ((proj2)*(Sq_Circ|K1)) = dom (Sq_Circ|K1) by A1,XBOOLE_0:def 10
.=dom Sq_Circ /\ K1 by FUNCT_1:68
.=(the carrier of TOP-REAL 2)/\ K1 by FUNCT_2:def 1
.=K1 by XBOOLE_1:28
.=the carrier of (TOP-REAL 2)|K1 by JORDAN1:1;
end;

Lm10:for K1 being non empty Subset of TOP-REAL 2 holds
  dom ((proj1)*(Sq_Circ|K1)) = the carrier of (TOP-REAL 2)|K1
proof
 let K1 be non empty Subset of TOP-REAL 2;
A1:dom ((proj1)*(Sq_Circ|K1)) c= dom (Sq_Circ|K1) by RELAT_1:44;
 dom (Sq_Circ|K1) c= dom ((proj1)*(Sq_Circ|K1))
proof let x be set;assume A2:x in dom (Sq_Circ|K1);
   then A3:x in dom Sq_Circ /\ K1 by FUNCT_1:68;
   A4:(Sq_Circ|K1).x=Sq_Circ.x by A2,FUNCT_1:68;
     x in dom Sq_Circ by A3,XBOOLE_0:def 3;
   then Sq_Circ.x in rng Sq_Circ by FUNCT_1:12;
  hence x in dom ((proj1)*(Sq_Circ|K1)) by A2,A4,Lm3,FUNCT_1:21;
end;
hence dom ((proj1)*(Sq_Circ|K1))
=dom (Sq_Circ|K1) by A1,XBOOLE_0:def 10
.=dom Sq_Circ /\ K1 by FUNCT_1:68
.=((the carrier of TOP-REAL 2))/\ K1 by FUNCT_2:def 1
.=K1 by XBOOLE_1:28
.=the carrier of (TOP-REAL 2)|K1 by JORDAN1:1;
end;

Lm11:(the carrier of TOP-REAL 2) \ {0.REAL 2} <> {} by JGRAPH_2:19;

theorem Th25: for K0,B0 being Subset of TOP-REAL 2,f being
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0
st f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2}
holds f is continuous
proof let K0,B0 be Subset of TOP-REAL 2,f be
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0;
assume A1:f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2};
     then 1.REAL 2 in K0 by Lm8;
then reconsider K1=K0 as non empty Subset of TOP-REAL 2;
A2:rng ((proj2)*(Sq_Circ|K1)) c= rng (proj2) by RELAT_1:45;
A3:dom ((proj2)*(Sq_Circ|K1)) = the carrier of (TOP-REAL 2)|K1 by Lm9;
  rng proj2 c= the carrier of R^1 by JGRAPH_2:17,RELSET_1:12;
then rng ((proj2)*(Sq_Circ|K1)) c= the carrier of R^1 by A2,XBOOLE_1:1;
then (proj2)*(Sq_Circ|K1) is Function of the carrier of (TOP-REAL 2)|K1,
the carrier of R^1 by A3,FUNCT_2:4;
then reconsider g2=(proj2)*(Sq_Circ|K1) as map of (TOP-REAL 2)|K1,R^1
                                ;
A4:dom ((proj1)*(Sq_Circ|K1)) = the carrier of (TOP-REAL 2)|K1 by Lm10;
A5:rng ((proj1)*(Sq_Circ|K1)) c= rng (proj1) by RELAT_1:45;
  rng proj1 c= the carrier of R^1 by JGRAPH_2:16,RELSET_1:12;
then rng ((proj1)*(Sq_Circ|K1)) c= the carrier of R^1 by A5,XBOOLE_1:1;
then (proj1)*(Sq_Circ|K1) is Function of the carrier of (TOP-REAL 2)|K1,
the carrier of R^1 by A4,FUNCT_2:4;
then reconsider g1=(proj1)*(Sq_Circ|K1) as map of (TOP-REAL 2)|K1,R^1
                                ;
A6: now let q be Point of TOP-REAL 2;
    assume A7:q in the carrier of (TOP-REAL 2)|K1;
        the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A8: q=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A7;
       now assume A9:q`1=0;
        then q`2=0 by A8;
      hence contradiction by A8,A9,EUCLID:57,58;
     end;
    hence q`1<>0;
   end;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g2.p=p`2/sqrt(1+(p`2/p`1)^2)
   proof let p be Point of TOP-REAL 2;
    assume A10: p in the carrier of (TOP-REAL 2)|K1;
     A11:dom (Sq_Circ|K1)=dom Sq_Circ /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A12:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A13: p=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A10;
     A14:Sq_Circ.p
     =|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]| by A13,Def1;
      (Sq_Circ|K1).p=Sq_Circ.p by A10,A12,FUNCT_1:72;
     then g2.p=(proj2).(|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|)
                             by A10,A11,A12,A14,FUNCT_1:23
      .=(|[p`1/sqrt(1+(p`2/p`1)^2),
        p`2/sqrt(1+(p`2/p`1)^2)]|)`2 by PSCOMP_1:def 29
      .=p`2/sqrt(1+(p`2/p`1)^2) by EUCLID:56;
    hence g2.p=p`2/sqrt(1+(p`2/p`1)^2);
   end;
then consider f2 being map of (TOP-REAL 2)|K1,R^1 such that
  A15:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f2.p=p`2/sqrt(1+(p`2/p`1)^2);
A16:f2 is continuous by A6,A15,Th22;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g1.p=p`1/sqrt(1+(p`2/p`1)^2)
   proof let p be Point of TOP-REAL 2;
    assume A17: p in the carrier of (TOP-REAL 2)|K1;
     A18:dom (Sq_Circ|K1)=dom Sq_Circ /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A19:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A20: p=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A17;
     A21:Sq_Circ.p=|[p`1/sqrt(1+(p`2/p`1)^2),
               p`2/sqrt(1+(p`2/p`1)^2)]| by A20,Def1;
      (Sq_Circ|K1).p=Sq_Circ.p by A17,A19,FUNCT_1:72;
     then g1.p=(proj1).(|[p`1/sqrt(1+(p`2/p`1)^2),
          p`2/sqrt(1+(p`2/p`1)^2)]|) by A17,A18,A19,A21,FUNCT_1:23
        .=(|[p`1/sqrt(1+(p`2/p`1)^2),
           p`2/sqrt(1+(p`2/p`1)^2)]|)`1 by PSCOMP_1:def 28
        .=p`1/sqrt(1+(p`2/p`1)^2) by EUCLID:56;
    hence g1.p=p`1/sqrt(1+(p`2/p`1)^2);
   end;
then consider f1 being map of (TOP-REAL 2)|K1,R^1 such that
  A22:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f1.p=p`1/sqrt(1+(p`2/p`1)^2);
A23:f1 is continuous by A6,A22,Th21;
  for x,y,r,s being real number st |[x,y]| in K1 &
  r=f1.(|[x,y]|) & s=f2.(|[x,y]|) holds f.(|[x,y]|)=|[r,s]|
  proof let x,y,r,s be real number;
   assume A24: |[x,y]| in K1 & r=f1.(|[x,y]|) & s=f2.(|[x,y]|);
     set p99=|[x,y]|;
     A25:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     consider p3 being Point of TOP-REAL 2 such that
     A26: p99=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A24;
     A27:f1.p99=p99`1/sqrt(1+(p99`2/p99`1)^2) by A22,A24,A25;
      (Sq_Circ|K0).(|[x,y]|)=(Sq_Circ).(|[x,y]|) by A24,FUNCT_1:72
    .= |[p99`1/sqrt(1+(p99`2/p99`1)^2),
    p99`2/sqrt(1+(p99`2/p99`1)^2)]| by A26,Def1
    .=|[r,s]| by A15,A24,A25,A27;
   hence f.(|[x,y]|)=|[r,s]| by A1;
  end;
hence thesis by A1,A16,A23,Lm11,JGRAPH_2:45;
end;

Lm12: ((1.REAL 2)`1<=(1.REAL 2)`2 & -(1.REAL 2)`2<=(1.REAL 2)`1 or
    (1.REAL 2)`1>=(1.REAL 2)`2 & (1.REAL 2)`1<=-(1.REAL 2)`2) &
    (1.REAL 2)<>0.REAL 2 by JGRAPH_2:13,REVROT_1:19;

theorem Th26: for K0,B0 being Subset of TOP-REAL 2,f being
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0
st f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2}
holds f is continuous
proof let K0,B0 be Subset of TOP-REAL 2,f be
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0;
assume A1:f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2};
     then 1.REAL 2 in K0 by Lm12;
then reconsider K1=K0 as non empty Subset of TOP-REAL 2;
A2:dom ((proj1)*(Sq_Circ|K1))=the carrier of (TOP-REAL 2)|K1 by Lm10;
A3:rng ((proj1)*(Sq_Circ|K1)) c= rng (proj1) by RELAT_1:45;
  rng proj1 c= the carrier of R^1 by JGRAPH_2:16,RELSET_1:12;
then rng ((proj1)*(Sq_Circ|K1)) c= the carrier of R^1 by A3,XBOOLE_1:1;
then (proj1)*(Sq_Circ|K1) is Function of the carrier of (TOP-REAL 2)|K1,
the carrier of R^1 by A2,FUNCT_2:4;
then reconsider g2=(proj1)*(Sq_Circ|K1) as map of (TOP-REAL 2)|K1,R^1
                                ;
A4:dom ((proj2)*(Sq_Circ|K1))=the carrier of (TOP-REAL 2)|K1 by Lm9;
A5:rng ((proj2)*(Sq_Circ|K1)) c= rng (proj2) by RELAT_1:45;
  rng proj2 c= the carrier of R^1 by JGRAPH_2:17,RELSET_1:12;
then rng ((proj2)*(Sq_Circ|K1)) c= the carrier of R^1 by A5,XBOOLE_1:1;
then (proj2)*(Sq_Circ|K1) is Function of the carrier of (TOP-REAL 2)|K1,
the carrier of R^1 by A4,FUNCT_2:4;
then reconsider g1=(proj2)*(Sq_Circ|K1) as map of (TOP-REAL 2)|K1,R^1
                                ;
A6: for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0
   proof let q be Point of TOP-REAL 2;
    assume A7:q in the carrier of (TOP-REAL 2)|K1;
        the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A8: q=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A7;
       now assume A9:q`2=0;
        then q`1=0 by A8;
      hence contradiction by A8,A9,EUCLID:57,58;
     end;
    hence q`2<>0;
   end;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g2.p=p`1/sqrt(1+(p`1/p`2)^2)
   proof let p be Point of TOP-REAL 2;
    assume A10: p in the carrier of (TOP-REAL 2)|K1;
     A11:dom (Sq_Circ|K1)=dom Sq_Circ /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A12:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A13: p=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A10;
     A14:Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),
         p`2/sqrt(1+(p`1/p`2)^2)]| by A13,Th14;
      (Sq_Circ|K1).p=Sq_Circ.p by A10,A12,FUNCT_1:72;
     then g2.p=(proj1).(|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|)
                             by A10,A11,A12,A14,FUNCT_1:23
        .=(|[p`1/sqrt(1+(p`1/p`2)^2),
            p`2/sqrt(1+(p`1/p`2)^2)]|)`1 by PSCOMP_1:def 28
        .=p`1/sqrt(1+(p`1/p`2)^2) by EUCLID:56;
    hence g2.p=p`1/sqrt(1+(p`1/p`2)^2);
   end;
then consider f2 being map of (TOP-REAL 2)|K1,R^1 such that
  A15:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f2.p=p`1/sqrt(1+(p`1/p`2)^2);
A16:f2 is continuous by A6,A15,Th24;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g1.p=p`2/sqrt(1+(p`1/p`2)^2)
   proof let p be Point of TOP-REAL 2;
    assume A17: p in the carrier of (TOP-REAL 2)|K1;
     A18:dom (Sq_Circ|K1)=dom Sq_Circ /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A19:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A20: p=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A17;
     A21:Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),
           p`2/sqrt(1+(p`1/p`2)^2)]| by A20,Th14;
      (Sq_Circ|K1).p=Sq_Circ.p by A17,A19,FUNCT_1:72;
     then g1.p=(proj2).(|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|)
                             by A17,A18,A19,A21,FUNCT_1:23
        .=(|[p`1/sqrt(1+(p`1/p`2)^2),
          p`2/sqrt(1+(p`1/p`2)^2)]|)`2 by PSCOMP_1:def 29
        .=p`2/sqrt(1+(p`1/p`2)^2) by EUCLID:56;
    hence g1.p=p`2/sqrt(1+(p`1/p`2)^2);
   end;
then consider f1 being map of (TOP-REAL 2)|K1,R^1 such that
  A22:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f1.p=p`2/sqrt(1+(p`1/p`2)^2);
A23:f1 is continuous by A6,A22,Th23;
    now let x,y,s,r be real number;
   assume A24: |[x,y]| in K1 & s=f2.(|[x,y]|) & r=f1.(|[x,y]|);
     set p99=|[x,y]|;
     A25:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     consider p3 being Point of TOP-REAL 2 such that
     A26: p99=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A24;
     A27:f1.p99=p99`2/sqrt(1+(p99`1/p99`2)^2) by A22,A24,A25;
      (Sq_Circ|K0).(|[x,y]|)=(Sq_Circ).(|[x,y]|) by A24,FUNCT_1:72
    .= |[p99`1/sqrt(1+(p99`1/p99`2)^2),
       p99`2/sqrt(1+(p99`1/p99`2)^2)]| by A26,Th14
    .=|[s,r]| by A15,A24,A25,A27;
   hence f.(|[x,y]|)=|[s,r]| by A1;
  end;
hence thesis by A1,A16,A23,Lm11,JGRAPH_2:45;
end;

scheme TopIncl { P[set] } :
  { p: P[p] & p<>0.REAL 2 } c= (the carrier of TOP-REAL 2) \ {0.REAL 2}
proof
  let x be set;assume x in { p: P[p] & p<>0.REAL 2 };
  then consider p8 being Point of TOP-REAL 2 such that
  A1: x=p8 & P[p8] & p8<>0.REAL 2;
    not x in {0.REAL 2} by A1,TARSKI:def 1;
  hence thesis by A1,XBOOLE_0:def 4;
end;

scheme TopInter { P[set] } :
  { p: P[p] & p<>0.REAL 2 } =
   { p7 where p7 is Point of TOP-REAL 2 : P[p7]} /\
   ((the carrier of TOP-REAL 2) \ {0.REAL 2})
proof
  set K0 = { p: P[p] & p<>0.REAL 2 };
  set K1 = { p7 where p7 is Point of TOP-REAL 2 : P[p7]};
  set B0 = (the carrier of TOP-REAL 2) \ {0.REAL 2};
  A1:K1 /\ B0 c= K0
  proof let x be set;assume x in K1 /\ B0;
    then A2:x in K1 & x in B0 by XBOOLE_0:def 3;
    then consider p7 being Point of TOP-REAL 2 such that
    A3: p7=x & P[p7];
      x in the carrier of TOP-REAL 2 & not x in {0.REAL 2}
                             by A2,XBOOLE_0:def 4;
    then x <> 0.REAL 2 by TARSKI:def 1;
   hence x in K0 by A3;
  end;
    K0 c= K1 /\ B0
   proof let x be set;assume x in K0;
    then consider p being Point of TOP-REAL 2 such that
    A4: x=p & P[p] & p<>0.REAL 2;
      x in the carrier of TOP-REAL 2 & not x in {0.REAL 2}
                             by A4,TARSKI:def 1;
    then x in K1 & x in B0 by A4,XBOOLE_0:def 4;
   hence x in K1 /\ B0 by XBOOLE_0:def 3;
   end;
   hence thesis by A1,XBOOLE_0:def 10;
end;

theorem Th27: for B0 being Subset of TOP-REAL 2,K0 being Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0)
st f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2}
& K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2}
holds f is continuous & K0 is closed
proof let B0 be Subset of TOP-REAL 2,K0 be Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0);
assume A1: f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2}
  & K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2};
    the carrier of (TOP-REAL 2)|B0 = B0 by JORDAN1:1;
  then K0 c= the carrier of TOP-REAL 2 by XBOOLE_1:1;
  then reconsider K1=K0 as Subset of TOP-REAL 2;
  defpred P[Point of TOP-REAL 2] means
  ($1`2<=$1`1 & -$1`1<=$1`2 or $1`2>=$1`1 & $1`2<=-$1`1);
    {p:P[p] & p<>0.REAL 2} c=
  (the carrier of TOP-REAL 2) \ {0.REAL 2} from TopIncl;
  then A2: ((TOP-REAL 2)|B0)|K0=(TOP-REAL 2)|K1 by A1,JORDAN6:47;
  defpred P[Point of TOP-REAL 2] means
    ($1`2<=$1`1 & -$1`1<=$1`2 or $1`2>=$1`1 & $1`2<=-$1`1);
  reconsider K1={p7 where p7 is Point of TOP-REAL 2: P[p7]}
    as Subset of TOP-REAL 2 from TopSubset;
  reconsider K2={p7 where p7 is Point of TOP-REAL 2: p7`2<=p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K3={p7 where p7 is Point of TOP-REAL 2: -p7`1<=p7`2 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:57;
  reconsider K4={p7 where p7 is Point of TOP-REAL 2: p7`1<=p7`2 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K5={p7 where p7 is Point of TOP-REAL 2:p7`2<=-p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:57;
  A3:K2 /\ K3 is closed by TOPS_1:35;
  A4:K4 /\ K5 is closed by TOPS_1:35;
  A5:K2 /\ K3 \/ K4 /\ K5 c= K1
  proof let x be set;assume
    A6:x in K2 /\ K3 \/ K4 /\ K5;
    per cases by A6,XBOOLE_0:def 2;
    suppose x in K2 /\ K3;
      then A7:x in K2 & x in K3 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A8: p7=x & p7`2<=(p7`1);
      consider p8 being Point of TOP-REAL 2 such that
      A9: p8=x & -p8`1<=p8`2 by A7;
     thus x in K1 by A8,A9;
    suppose x in K4 /\ K5;
      then A10:x in K4 & x in K5 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A11: p7=x & p7`2>=(p7`1);
      consider p8 being Point of TOP-REAL 2 such that
      A12: p8=x & p8`2<= -p8`1 by A10;
     thus x in K1 by A11,A12;
  end;
    K1 c= K2 /\ K3 \/ K4 /\ K5
   proof let x be set;assume x in K1;
     then consider p being Point of TOP-REAL 2 such that
     A13: p=x & (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
       x in K2 & x in K3 or x in K4 & x in K5 by A13;
     then x in K2 /\ K3 or x in K4 /\ K5 by XBOOLE_0:def 3;
    hence x in K2 /\ K3 \/ K4 /\ K5 by XBOOLE_0:def 2;
   end;
  then K1=K2 /\ K3 \/ K4 /\ K5 by A5,XBOOLE_0:def 10;
  then A14:K1 is closed by A3,A4,TOPS_1:36;
  defpred P[Point of TOP-REAL 2] means
    ($1`2<=$1`1 & -$1`1<=$1`2 or $1`2>=$1`1 & $1`2<=-$1`1);
    {p: P[p] & p<>0.REAL 2} =
  {p7 where p7 is Point of TOP-REAL 2: P[p7]}
   /\ ((the carrier of TOP-REAL 2) \ {0.REAL 2}) from TopInter;
  then K0=K1 /\ [#]((TOP-REAL 2)|B0) by A1,PRE_TOPC:def 10;
hence thesis by A1,A2,A14,Th25,PRE_TOPC:43;
end;

theorem Th28: for B0 being Subset of TOP-REAL 2,K0 being Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0)
st f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2}
& K0={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2}
holds f is continuous & K0 is closed
proof let B0 be Subset of TOP-REAL 2,K0 be Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0);
assume A1: f=Sq_Circ|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2}
  & K0={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2};
  defpred P0[Point of TOP-REAL 2] means
  ($1`1<=$1`2 & -$1`2<=$1`1 or $1`1>=$1`2 & $1`1<=-$1`2);
  set k0 = {p:P0[p] & p<>0.REAL 2};
  set b0 = (the carrier of TOP-REAL 2) \ {0.REAL 2};
    the carrier of (TOP-REAL 2)|B0= B0 by JORDAN1:1;
  then K0 c= the carrier of TOP-REAL 2 by XBOOLE_1:1;
  then reconsider K1=K0 as Subset of TOP-REAL 2;
  defpred P[Point of TOP-REAL 2] means
  ($1`1<=$1`2 & -$1`2<=$1`1 or $1`1>=$1`2 & $1`1<=-$1`2);
    {p:P[p] & p<>0.REAL 2} c=
    (the carrier of TOP-REAL 2) \ {0.REAL 2} from TopIncl;
  then A2: ((TOP-REAL 2)|B0)|K0=(TOP-REAL 2)|K1 by A1,JORDAN6:47;
  defpred P[Point of TOP-REAL 2] means
  ($1`1<=$1`2 & -$1`2<=$1`1 or $1`1>=$1`2 & $1`1<=-$1`2);
  reconsider K1={p7 where p7 is Point of TOP-REAL 2:P[p7]}
  as Subset of TOP-REAL 2 from TopSubset;
  reconsider K2={p7 where p7 is Point of TOP-REAL 2: p7`1<=p7`2 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K3={p7 where p7 is Point of TOP-REAL 2: -p7`2<=p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:58;
  reconsider K4={p7 where p7 is Point of TOP-REAL 2: p7`2<=p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K5={p7 where p7 is Point of TOP-REAL 2: p7`1<=-p7`2 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:58;
  A3:K2 /\ K3 is closed by TOPS_1:35;
  A4:K4 /\ K5 is closed by TOPS_1:35;
  A5:K2 /\ K3 \/ K4 /\ K5 c= K1
  proof let x be set;assume
    A6:x in K2 /\ K3 \/ K4 /\ K5;
    per cases by A6,XBOOLE_0:def 2;
    suppose x in K2 /\ K3;
      then A7:x in K2 & x in K3 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A8: p7=x & p7`1<=(p7`2);
      consider p8 being Point of TOP-REAL 2 such that
      A9: p8=x & -p8`2<=p8`1 by A7;
     thus x in K1 by A8,A9;
    suppose x in K4 /\ K5;
      then A10:x in K4 & x in K5 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A11: p7=x & p7`1>=(p7`2);
      consider p8 being Point of TOP-REAL 2 such that
      A12: p8=x & p8`1<= -p8`2 by A10;
     thus x in K1 by A11,A12;
  end;
    K1 c= K2 /\ K3 \/ K4 /\ K5
   proof let x be set;assume x in K1;
     then consider p being Point of TOP-REAL 2 such that
     A13: p=x &
      (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2);
       x in K2 & x in K3 or x in K4 & x in K5 by A13;
     then x in K2 /\ K3 or x in K4 /\ K5 by XBOOLE_0:def 3;
    hence x in K2 /\ K3 \/ K4 /\ K5 by XBOOLE_0:def 2;
   end;
  then K1=K2 /\ K3 \/ K4 /\ K5 by A5,XBOOLE_0:def 10;
  then A14:K1 is closed by A3,A4,TOPS_1:36;
    k0 = {p7 where p7 is Point of TOP-REAL 2:P0[p7]} /\ b0
  from TopInter;
  then K0=K1 /\ [#]((TOP-REAL 2)|B0) by A1,PRE_TOPC:def 10;
hence thesis by A1,A2,A14,Th26,PRE_TOPC:43;
end;

theorem Th29:for D being non empty Subset of TOP-REAL 2
st D`={0.REAL 2} holds
ex h being map of (TOP-REAL 2)|D,(TOP-REAL 2)|D
st h=Sq_Circ|D & h is continuous
proof let D be non empty Subset of TOP-REAL 2;
assume A1:D`={0.REAL 2};
  then A2: D = {0.REAL 2}`
     .=((the carrier of TOP-REAL 2)\ {0.REAL 2}) by SUBSET_1:def 5;
    A3:{p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
       & p<>0.REAL 2} c= the carrier of (TOP-REAL 2)|D
       proof let x be set;
        assume x in {p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
       & p<>0.REAL 2};
         then consider p such that A4: x=p &
         (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2;
           now assume not x in D;
           then x in (the carrier of TOP-REAL 2) \ D by A4,XBOOLE_0:def 4;
           then x in D` by SUBSET_1:def 5;
          hence contradiction by A1,A4,TARSKI:def 1;
         end;
        hence x in the carrier of (TOP-REAL 2)|D by JORDAN1:1;
       end;
        1.REAL 2 in {p where p is Point of TOP-REAL 2:
        (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
          & p<>0.REAL 2} by Lm8;
   then reconsider K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
  & p<>0.REAL 2} as non empty Subset of (TOP-REAL 2)|D by A3;
    A5:{p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
       & p<>0.REAL 2} c= the carrier of (TOP-REAL 2)|D
       proof let x be set;
        assume x in {p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
       & p<>0.REAL 2};
         then consider p such that A6: x=p &
         (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)& p<>0.REAL 2;
           now assume not x in D;
           then x in (the carrier of TOP-REAL 2) \ D by A6,XBOOLE_0:def 4;
           then x in D` by SUBSET_1:def 5;
          hence contradiction by A1,A6,TARSKI:def 1;
         end;
        hence x in the carrier of (TOP-REAL 2)|D by JORDAN1:1;
       end;
     set Y1=|[-1,1]|;
      Y1`1=-1 & Y1`2=1 by EUCLID:56;
     then Y1 in {p where p is Point of TOP-REAL 2:
     (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
       & p<>0.REAL 2} by JGRAPH_2:11;
  then reconsider K1={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
  & p<>0.REAL 2} as non empty Subset of (TOP-REAL 2)|D by A5;
   A7:the carrier of ((TOP-REAL 2)|D) =D by JORDAN1:1;
   A8:K0 c= the carrier of TOP-REAL 2
   proof let z be set;assume z in K0;
     then consider p8 being Point of TOP-REAL 2 such that
     A9: p8=z &((p8`2<=p8`1 & -p8`1<=p8`2 or p8`2>=p8`1 & p8`2<=-p8`1)
     & p8<>0.REAL 2);
    thus z in the carrier of TOP-REAL 2 by A9;
   end;
  A10:dom (Sq_Circ|K0)= dom (Sq_Circ) /\ K0 by FUNCT_1:68
       .=((the carrier of TOP-REAL 2)) /\ K0 by FUNCT_2:def 1
       .=K0 by A8,XBOOLE_1:28;
  A11: K0=the carrier of ((TOP-REAL 2)|D)|K0 by JORDAN1:1;
    rng (Sq_Circ|K0) c= the carrier of ((TOP-REAL 2)|D)|K0
   proof let y be set;assume y in rng (Sq_Circ|K0);
     then consider x being set such that
     A12:x in dom (Sq_Circ|K0) & y=(Sq_Circ|K0).x by FUNCT_1:def 5;
     A13:x in (dom Sq_Circ) /\ K0 by A12,FUNCT_1:68;
     then A14:x in K0 by XBOOLE_0:def 3;
     A15: K0 c= the carrier of TOP-REAL 2 by A7,XBOOLE_1:1;
     then reconsider p=x as Point of TOP-REAL 2 by A14;
     A16:Sq_Circ.p=y by A12,A14,FUNCT_1:72;
     consider px being Point of TOP-REAL 2 such that A17: x=px &
         (px`2<=px`1 & -px`1<=px`2 or px`2>=px`1 & px`2<=-px`1)
         & px<>0.REAL 2 by A14;
     reconsider K00=K0 as Subset of TOP-REAL 2 by A15;
       K00=the carrier of ((TOP-REAL 2)|K00) by JORDAN1:1;
     then A18:p in the carrier of ((TOP-REAL 2)|K00) by A13,XBOOLE_0:def 3;
  for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K00 holds q`1<>0
   proof let q be Point of TOP-REAL 2;
    assume A19:q in the carrier of (TOP-REAL 2)|K00;
        the carrier of (TOP-REAL 2)|K00=K0 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A20: q=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A19;
       now assume A21:q`1=0;
        then q`2=0 by A20;
      hence contradiction by A20,A21,EUCLID:57,58;
     end;
    hence q`1<>0;
   end;
     then A22:p`1<>0 by A18;
     set p9=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|;
     A23:p9`1=p`1/sqrt(1+(p`2/p`1)^2) & p9`2=p`2/sqrt(1+(p`2/p`1)^2)
                                     by EUCLID:56;
        1+(p`2/p`1)^2>0 by Lm1;
      then A24:sqrt(1+(p`2/p`1)^2)>0 by SQUARE_1:93;
     A25:now assume p9=0.REAL 2;
       then 0 *sqrt(1+(p`2/p`1)^2)=p`1/sqrt(1+(p`2/p`1)^2)*sqrt(1+(p`2/p`1)^2)
                                    by A23,EUCLID:56,58;
      hence contradiction by A22,A24,XCMPLX_1:88;
     end;
     A26:Sq_Circ.p=|[p`1/sqrt(1+(p`2/p`1)^2),
     p`2/sqrt(1+(p`2/p`1)^2)]| by A17,Def1;
       p`2/sqrt(1+(p`2/p`1)^2)<=p`1/sqrt(1+(p`2/p`1)^2)
     & (-p`1)/sqrt(1+(p`2/p`1)^2)<=p`2/sqrt(1+(p`2/p`1)^2) or
     p`2/sqrt(1+(p`2/p`1)^2)>=p`1/sqrt(1+(p`2/p`1)^2) &
     p`2/sqrt(1+(p`2/p`1)^2)<=(-p`1)/sqrt(1+(p`2/p`1)^2)
                       by A17,A24,REAL_1:73;
     then A27:p`2/sqrt(1+(p`2/p`1)^2)<=p`1/sqrt(1+(p`2/p`1)^2)
     & -(p`1/sqrt(1+(p`2/p`1)^2))<=p`2/sqrt(1+(p`2/p`1)^2) or
     p`2/sqrt(1+(p`2/p`1)^2)>=p`1/sqrt(1+(p`2/p`1)^2) &
     p`2/sqrt(1+(p`2/p`1)^2)<=-(p`1/sqrt(1+(p`2/p`1)^2)) by XCMPLX_1:188;
       p9`1=p`1/sqrt(1+(p`2/p`1)^2) & p9`2=p`2/sqrt(1+(p`2/p`1)^2) by EUCLID:56
;
      then y in K0 by A16,A25,A26,A27;
     then y in [#](((TOP-REAL 2)|D)|K0) by PRE_TOPC:def 10;
    hence y in the carrier of ((TOP-REAL 2)|D)|K0;
   end;
  then rng (Sq_Circ|K0)c= the carrier of ((TOP-REAL 2)|D) by A11,XBOOLE_1:1;
  then Sq_Circ|K0 is Function of the carrier of ((TOP-REAL 2)|D)|K0,
  the carrier of ((TOP-REAL 2)|D) by A10,A11,FUNCT_2:4;
  then reconsider f=Sq_Circ|K0 as map of ((TOP-REAL 2)|D)|K0,
  (TOP-REAL 2)|D ;
   A28:K1 c= the carrier of TOP-REAL 2
   proof let z be set;assume z in K1;
     then consider p8 being Point of TOP-REAL 2 such that
     A29: p8=z &((p8`1<=p8`2 & -p8`2<=p8`1 or p8`1>=p8`2 & p8`1<=-p8`2)
      & p8<>0.REAL 2);
    thus z in the carrier of TOP-REAL 2 by A29;
   end;
  A30:dom (Sq_Circ|K1)= dom (Sq_Circ) /\ K1 by FUNCT_1:68
       .=((the carrier of TOP-REAL 2)) /\ K1 by FUNCT_2:def 1
       .=K1 by A28,XBOOLE_1:28;
  A31: K1=the carrier of ((TOP-REAL 2)|D)|K1 by JORDAN1:1;
    rng (Sq_Circ|K1) c= the carrier of ((TOP-REAL 2)|D)|K1
   proof let y be set;assume y in rng (Sq_Circ|K1);
     then consider x being set such that
     A32:x in dom (Sq_Circ|K1) & y=(Sq_Circ|K1).x by FUNCT_1:def 5;
     A33:x in (dom Sq_Circ) /\ K1 by A32,FUNCT_1:68;
     then A34:x in K1 by XBOOLE_0:def 3;
     then reconsider p=x as Point of TOP-REAL 2 by A28;
     A35:Sq_Circ.p=y by A32,A34,FUNCT_1:72;
     consider px being Point of TOP-REAL 2 such that A36: x=px &
         (px`1<=px`2 & -px`2<=px`1 or px`1>=px`2 & px`1<=-px`2)
         & px<>0.REAL 2 by A34;
     reconsider K10=K1 as Subset of TOP-REAL 2 by A28;
       K10=the carrier of ((TOP-REAL 2)|K10) by JORDAN1:1;
     then A37:p in the carrier of ((TOP-REAL 2)|K10) by A33,XBOOLE_0:def 3;
  for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K10 holds q`2<>0
   proof let q be Point of TOP-REAL 2;
    assume A38:q in the carrier of (TOP-REAL 2)|K10;
        the carrier of (TOP-REAL 2)|K10=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A39: q=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A38;
       now assume A40:q`2=0;
        then q`1=0 by A39;
      hence contradiction by A39,A40,EUCLID:57,58;
     end;
    hence q`2<>0;
   end;
     then A41:p`2<>0 by A37;
     set p9=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|;
     A42:p9`1=p`1/sqrt(1+(p`1/p`2)^2) & p9`2=p`2/sqrt(1+(p`1/p`2)^2)
                                     by EUCLID:56;
        1+(p`1/p`2)^2>0 by Lm1;
      then A43:sqrt(1+(p`1/p`2)^2)>0 by SQUARE_1:93;
     A44:now assume p9=0.REAL 2;
       then 0 *sqrt(1+(p`1/p`2)^2)=p`2/sqrt(1+(p`1/p`2)^2)*sqrt(1+(p`1/p`2)^2)
                                    by A42,EUCLID:56,58;
      hence contradiction by A41,A43,XCMPLX_1:88;
     end;
     A45:Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),
        p`2/sqrt(1+(p`1/p`2)^2)]| by A36,Th14;
       p`1/sqrt(1+(p`1/p`2)^2)<=p`2/sqrt(1+(p`1/p`2)^2)
     & (-p`2)/sqrt(1+(p`1/p`2)^2)<=p`1/sqrt(1+(p`1/p`2)^2) or
     p`1/sqrt(1+(p`1/p`2)^2)>=p`2/sqrt(1+(p`1/p`2)^2) &
     p`1/sqrt(1+(p`1/p`2)^2)<=(-p`2)/sqrt(1+(p`1/p`2)^2)
                       by A36,A43,REAL_1:73;
     then A46:p`1/sqrt(1+(p`1/p`2)^2)<=p`2/sqrt(1+(p`1/p`2)^2)
     & -(p`2/sqrt(1+(p`1/p`2)^2))<=p`1/sqrt(1+(p`1/p`2)^2) or
     p`1/sqrt(1+(p`1/p`2)^2)>=p`2/sqrt(1+(p`1/p`2)^2) &
     p`1/sqrt(1+(p`1/p`2)^2)<=-(p`2/sqrt(1+(p`1/p`2)^2))
                       by XCMPLX_1:188;
        p9`2=p`2/sqrt(1+(p`1/p`2)^2) & p9`1=p`1/sqrt(1+(p`1/p`2)^2)
                                 by EUCLID:56;
      then y in K1 by A35,A44,A45,A46;
    hence y in the carrier of ((TOP-REAL 2)|D)|K1 by JORDAN1:1;
   end;
  then rng (Sq_Circ|K1)c= the carrier of ((TOP-REAL 2)|D) by A31,XBOOLE_1:1;
  then Sq_Circ|K1 is Function of the carrier of ((TOP-REAL 2)|D)|K1,
  the carrier of ((TOP-REAL 2)|D) by A30,A31,FUNCT_2:4;
  then reconsider g=Sq_Circ|K1 as map of ((TOP-REAL 2)|D)|K1,
  ((TOP-REAL 2)|D) ;
  A47:K0=[#](((TOP-REAL 2)|D)|K0) by PRE_TOPC:def 10;
  A48:K1=[#](((TOP-REAL 2)|D)|K1) by PRE_TOPC:def 10;
  A49:D= [#]((TOP-REAL 2)|D) by PRE_TOPC:def 10;
  A50:K0 \/ K1 c= D
   proof let x be set;assume A51:x in K0 \/ K1;
       now per cases by A51,XBOOLE_0:def 2;
     case x in K0;
       then consider p such that A52:p=x &
       (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2;
     thus x in the carrier of TOP-REAL 2 & not x=0.REAL 2 by A52;
     case x in K1;
       then consider p such that A53:p=x &
       (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
         & p<>0.REAL 2;
     thus x in the carrier of TOP-REAL 2 & not x=0.REAL 2 by A53;
     end;
     then x in the carrier of TOP-REAL 2 & not x in {0.REAL 2} by TARSKI:def 1
;
    hence x in D by A2,XBOOLE_0:def 4;
   end;
    D c= K0 \/ K1
   proof let x be set;assume A54: x in D;
     then A55:x in (the carrier of TOP-REAL 2) & not x in {0.REAL 2}
                                     by A2,XBOOLE_0:def 4;
     reconsider px=x as Point of TOP-REAL 2 by A54;
       (px`2<=px`1 & -px`1<=px`2 or px`2>=px`1 & px`2<=-px`1)
         & px<>0.REAL 2 or
       (px`1<=px`2 & -px`2<=px`1 or px`1>=px`2 & px`1<=-px`2)
         & px<>0.REAL 2 by A55,REAL_2:110,TARSKI:def 1;
     then x in K0 or x in K1;
    hence x in K0 \/ K1 by XBOOLE_0:def 2;
   end;
  then A56:([#](((TOP-REAL 2)|D)|K0)) \/ ([#](((TOP-REAL 2)|D)|K1))
  = [#]((TOP-REAL 2)|D) by A47,A48,A49,A50,XBOOLE_0:def 10;
    f=Sq_Circ|K0 & D=(the carrier of TOP-REAL 2) \ {0.REAL 2}
  & K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2}
                   by A2;
  then A57: f is continuous & K0 is closed by Th27;
    g=Sq_Circ|K1 & D=(the carrier of TOP-REAL 2) \ {0.REAL 2}
  & K1={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2}
                   by A2;
  then A58: g is continuous & K1 is closed by Th28;
  A59: for x be set st x in ([#](((TOP-REAL 2)|D)|K0))
        /\ ([#] (((TOP-REAL 2)|D)|K1)) holds f.x = g.x
   proof let x be set;assume x in ([#](((TOP-REAL 2)|D)|K0))
        /\ [#] (((TOP-REAL 2)|D)|K1);
     then A60:x in K0 & x in K1 by A47,A48,XBOOLE_0:def 3;
     then f.x=Sq_Circ.x by FUNCT_1:72;
    hence f.x = g.x by A60,FUNCT_1:72;
   end;
  then consider h being map of (TOP-REAL 2)|D,(TOP-REAL 2)|D
  such that A61: h= f+*g & h is continuous
                          by A47,A48,A56,A57,A58,JGRAPH_2:9;
  A62:dom h=the carrier of ((TOP-REAL 2)|D) by FUNCT_2:def 1;
  A63:the carrier of ((TOP-REAL 2)|D)=D by JORDAN1:1;
  A64:the carrier of ((TOP-REAL 2)|D)
       =[#](((TOP-REAL 2)|D)) by PRE_TOPC:12
       .=((the carrier of TOP-REAL 2)\ {0.REAL 2}) by A2,PRE_TOPC:def 10;
    dom Sq_Circ=(the carrier of (TOP-REAL 2)) by FUNCT_2:def 1;
  then A65:dom (Sq_Circ|D)=(the carrier of (TOP-REAL 2))/\ D by FUNCT_1:68
              .=the carrier of ((TOP-REAL 2)|D) by A63,XBOOLE_1:28;
  A66:dom f=K0 by A11,FUNCT_2:def 1;
  A67:K0=[#](((TOP-REAL 2)|D)|K0) by PRE_TOPC:def 10;
  A68:dom g=K1 by A31,FUNCT_2:def 1;
   K1=[#](((TOP-REAL 2)|D)|K1) by PRE_TOPC:def 10;
  then A69:f tolerates g by A59,A66,A67,A68,PARTFUN1:def 6;
    for x being set st x in dom h holds h.x=(Sq_Circ|D).x
   proof let x be set;assume A70: x in dom h;
     then x in (the carrier of TOP-REAL 2) & not x in {0.REAL 2}
                     by A64,XBOOLE_0:def 4;
     then A71:x <>0.REAL 2 by TARSKI:def 1;
     reconsider p=x as Point of TOP-REAL 2 by A64,A70,XBOOLE_0:def 4;
       x in (the carrier of TOP-REAL 2)\D` by A1,A64,A70;
then A72:x in D`` by SUBSET_1:def 5;
     per cases;
     suppose A73:x in K0;
       A74:Sq_Circ|D.p=Sq_Circ.p by A72,FUNCT_1:72.=f.p by A73,FUNCT_1:72;
         h.p=(g+*f).p by A61,A69,FUNCT_4:35 .=f.p by A66,A73,FUNCT_4:14;
      hence thesis by A74;
     suppose not x in K0;
       then not (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) by A71;
       then (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)by REAL_2:110;
       then A75:x in K1 by A71;
         Sq_Circ|D.p=Sq_Circ.p by A72,FUNCT_1:72.=g.p by A75,FUNCT_1:72;
      hence thesis by A61,A68,A75,FUNCT_4:14;
   end;
  then f+*g=Sq_Circ|D by A61,A62,A65,FUNCT_1:9;
 hence thesis by A47,A48,A56,A57,A58,A59,JGRAPH_2:9;
end;

theorem Th30:
for D being non empty Subset of TOP-REAL 2 st
    D=(the carrier of TOP-REAL 2) \ {0.REAL 2} holds D`= {0.REAL 2}
proof
 let D be non empty Subset of TOP-REAL 2;
 assume A1:D=(the carrier of TOP-REAL 2) \{0.REAL 2};
 A2:{0.REAL 2} c= D`
  proof let x be set;assume A3: x in {0.REAL 2};
    then not x in D by A1,XBOOLE_0:def 4;
    then x in (the carrier of TOP-REAL 2)\D by A3,XBOOLE_0:def 4;
   hence x in D` by SUBSET_1:def 5;
  end;
   D` c= {0.REAL 2}
  proof let x be set;assume x in D`;
    then x in (the carrier of TOP-REAL 2)\D by SUBSET_1:def 5;
    then x in (the carrier of TOP-REAL 2) & not x in D by XBOOLE_0:def 4;
   hence x in {0.REAL 2} by A1,XBOOLE_0:def 4;
  end;
 hence thesis by A2,XBOOLE_0:def 10;
end;

theorem Th31:
ex h being map of TOP-REAL 2, TOP-REAL 2 st h=Sq_Circ & h is continuous
proof
 reconsider f=Sq_Circ as map of (TOP-REAL 2),(TOP-REAL 2) ;
  (the carrier of TOP-REAL 2) \{0.REAL 2} c=(the carrier of TOP-REAL 2)
                         by XBOOLE_1:36;
 then reconsider D=(the carrier of TOP-REAL 2) \{0.REAL 2}
   as non empty Subset of TOP-REAL 2 by JGRAPH_2:19;
 A1: f.(0.REAL 2)=0.REAL 2 by Def1;
 A2: D`= {0.REAL 2} by Th30;
 A3: for p being Point of (TOP-REAL 2)|D holds f.p<>f.(0.REAL 2)
  proof let p be Point of (TOP-REAL 2)|D;
    A4:the carrier of (TOP-REAL 2)|D=[#]((TOP-REAL 2)|D) by PRE_TOPC:12;
    A5:[#]((TOP-REAL 2)|D)=D by PRE_TOPC:def 10;
    then A6:p in the carrier of TOP-REAL 2 & not p in {0.REAL 2}
                         by A4,XBOOLE_0:def 4;
    reconsider q=p as Point of TOP-REAL 2 by A4,A5,XBOOLE_0:def 4;
    A7:not p=0.REAL 2 by A6,TARSKI:def 1;
    per cases;
    suppose A8:not(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
      then A9:Sq_Circ.q=|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|
                        by A7,Def1;
      A10:q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 & q`1<=-q`2 by A8,JGRAPH_2:23;
      A11:now assume A12:q`2=0;
        then q`1=0 by A10;
       hence contradiction by A7,A12,EUCLID:57,58;
      end;
      set q9=|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|;
      A13:q9`1=q`1/sqrt(1+(q`1/q`2)^2) & q9`2=q`2/sqrt(1+(q`1/q`2)^2)
                                  by EUCLID:56;
        1+(q`1/q`2)^2>0 by Lm1;
      then A14:sqrt(1+(q`1/q`2)^2)>0 by SQUARE_1:93;
        now assume q9=0.REAL 2;
       then 0 *sqrt(1+(q`1/q`2)^2)=q`2/sqrt(1+(q`1/q`2)^2)*sqrt(1+(q`1/q`2)^2)
                             by A13,EUCLID:56,58;
      hence contradiction by A11,A14,XCMPLX_1:88;
     end;
     hence thesis by A9,Def1;
    suppose A15:q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1;
      then A16:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|
                        by A7,Def1;
      A17:now assume A18:q`1=0;
        then q`2=0 by A15;
       hence contradiction by A7,A18,EUCLID:57,58;
      end;
      set q9=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|;
      A19:q9`1=q`1/sqrt(1+(q`2/q`1)^2) & q9`2=q`2/sqrt(1+(q`2/q`1)^2)
                                  by EUCLID:56;
        1+(q`2/q`1)^2>0 by Lm1;
      then A20:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
        now assume q9=0.REAL 2;
       then 0 *sqrt(1+(q`2/q`1)^2)=q`1/sqrt(1+(q`2/q`1)^2)*sqrt(1+(q`2/q`1)^2)
                           by A19,EUCLID:56,58;
      hence contradiction by A17,A20,XCMPLX_1:88;
     end;
     hence thesis by A16,Def1;
  end;
 A21:ex h being map of (TOP-REAL 2)|D,(TOP-REAL 2)|D
  st h=Sq_Circ|D & h is continuous by A2,Th29;
   for V being Subset of TOP-REAL 2 st f.(0.REAL 2) in V & V is open
 ex W being Subset of TOP-REAL 2 st 0.REAL 2 in W
 & W is open & f.:W c= V
  proof let V be Subset of (TOP-REAL 2);
    assume A22:f.(0.REAL 2) in V & V is open;
     A23:the carrier of TOP-REAL 2=REAL 2 by EUCLID:25;
     A24:Euclid 2=MetrStruct(#REAL 2,Pitag_dist 2#) by EUCLID:def 7;
     then reconsider u0=0.REAL 2 as Point of Euclid 2 by EUCLID:25;
     consider r being real number such that A25:r>0 & Ball(u0,r) c= V
                                   by A1,A22,Lm2,TOPMETR:22;
     reconsider r as Real by XREAL_0:def 1;
     reconsider W1=Ball(u0,r) as Subset of TOP-REAL 2
                       by A23,A24;
     A26:u0 in W1 by A25,GOBOARD6:4;
     A27:W1 is open by GOBOARD6:6;
       f.:W1 c= W1
      proof let z be set;assume z in f.:W1;
        then consider y being set such that
        A28: y in dom f & y in W1 & z=f.y by FUNCT_1:def 12;
        reconsider q=y as Point of TOP-REAL 2 by A28;
        reconsider qy=q as Point of Euclid 2 by A24,EUCLID:25;
          z in rng f by A28,FUNCT_1:def 5;
        then reconsider qz=z as Point of TOP-REAL 2;
        reconsider pz=qz as Point of Euclid 2 by A24,EUCLID:25;
          dist(u0,qy)<r by A28,METRIC_1:12;
        then |.(0.REAL 2) - q.|<r by JGRAPH_1:45;
        then sqrt((((0.REAL 2) - q)`1)^2+(((0.REAL 2) - q)`2)^2)<r by JGRAPH_1:
47;
        then sqrt(((0.REAL 2)`1 - q`1)^2+(((0.REAL 2) - q)`2)^2)<r
                                  by TOPREAL3:8;
        then sqrt(((0.REAL 2)`1 - q`1)^2+((0.REAL 2)`2 - q`2)^2)<r
                                  by TOPREAL3:8;
        then sqrt((- q`1)^2+(0 - q`2)^2)<r by JGRAPH_2:11,XCMPLX_1:150;
        then sqrt((- q`1)^2+(- q`2)^2)<r by XCMPLX_1:150;
        then sqrt((q`1)^2+(- q`2)^2)<r by SQUARE_1:61;
        then A29:sqrt((q`1)^2+(q`2)^2)<r by SQUARE_1:61;
        per cases;
        suppose q=0.REAL 2;
         hence thesis by A28,Def1;
        suppose q<>0.REAL 2 &
          (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          then A30:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)
]|
                                 by Def1;
          A31:((0.REAL 2) - qz)`1=(0.REAL 2)`1-qz`1 by TOPREAL3:8
                      .= -qz`1 by JGRAPH_2:11,XCMPLX_1:150;
          A32:((0.REAL 2) - qz)`2=(0.REAL 2)`2-qz`2 by TOPREAL3:8
                      .= -qz`2 by JGRAPH_2:11,XCMPLX_1:150;
            (q`2/q`1)^2 >=0 by SQUARE_1:72;
          then 1+(q`2/q`1)^2>=1+0 by REAL_1:55;
          then A33:sqrt(1+(q`2/q`1)^2)>=1 by Th8;
          then (sqrt(1+(q`2/q`1)^2))^2>=sqrt(1+(q`2/q`1)^2) by JGRAPH_2:2;
          then A34:1<=(sqrt(1+(q`2/q`1)^2))^2 by A33,AXIOMS:22;
          A35:(qz`1)^2=(q`1/sqrt(1+(q`2/q`1)^2))^2 by A28,A30,EUCLID:56
               .=(q`1)^2/(sqrt(1+(q`2/q`1)^2))^2 by SQUARE_1:69;
          A36:(qz`1)^2>=0 by SQUARE_1:72;
            (q`1)^2>=0 by SQUARE_1:72;
          then A37:(qz`1)^2<=(q`1)^2/1 by A34,A35,REAL_2:201;
          A38:(qz`2)^2=(q`2/sqrt(1+(q`2/q`1)^2))^2 by A28,A30,EUCLID:56
               .=(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2 by SQUARE_1:69;
          A39:(qz`2)^2>=0 by SQUARE_1:72;
            (q`2)^2>=0 by SQUARE_1:72;
          then A40:(qz`2)^2<=(q`2)^2/1 by A34,A38,REAL_2:201;
          A41:sqrt((((0.REAL 2) - qz)`1)^2+(((0.REAL 2) - qz)`2)^2)
          =sqrt((qz`1)^2+(-qz`2)^2) by A31,A32,SQUARE_1:61
          .=sqrt((qz`1)^2+(qz`2)^2) by SQUARE_1:61;
          A42:(qz`1)^2+(qz`2)^2<=(q`1)^2+(q`2)^2 by A37,A40,REAL_1:55;
            0+0<= (qz`1)^2+(qz`2)^2 by A36,A39,REAL_1:55;
          then sqrt((qz`1)^2+(qz`2)^2) <= sqrt((q`1)^2+(q`2)^2)
                          by A42,SQUARE_1:94;
          then sqrt((((0.REAL 2) - qz)`1)^2+(((0.REAL 2) - qz)`2)^2)<r
                           by A29,A41,AXIOMS:22;
          then |.(0.REAL 2) - qz.|<r by JGRAPH_1:47;
          then dist(u0,pz)<r by JGRAPH_1:45;
         hence thesis by METRIC_1:12;
        suppose q<>0.REAL 2 &
         not (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          then A43:Sq_Circ.q=|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)
]|
                        by Def1;
          A44:((0.REAL 2) - qz)`1=(0.REAL 2)`1-qz`1 by TOPREAL3:8
                      .= -qz`1 by JGRAPH_2:11,XCMPLX_1:150;
          A45:((0.REAL 2) - qz)`2=(0.REAL 2)`2-qz`2 by TOPREAL3:8
                      .= -qz`2 by JGRAPH_2:11,XCMPLX_1:150;
            (q`1/q`2)^2 >=0 by SQUARE_1:72;
          then 1+(q`1/q`2)^2>=1+0 by REAL_1:55;
          then A46:sqrt(1+(q`1/q`2)^2)>=1 by Th8;
          then (sqrt(1+(q`1/q`2)^2))^2>=sqrt(1+(q`1/q`2)^2) by JGRAPH_2:2;
          then A47:1<=(sqrt(1+(q`1/q`2)^2))^2 by A46,AXIOMS:22;
          A48:(qz`1)^2=(q`1/sqrt(1+(q`1/q`2)^2))^2 by A28,A43,EUCLID:56
               .=(q`1)^2/(sqrt(1+(q`1/q`2)^2))^2 by SQUARE_1:69;
          A49:(qz`1)^2>=0 by SQUARE_1:72;
            (q`1)^2>=0 by SQUARE_1:72;
          then A50:(qz`1)^2<=(q`1)^2/1 by A47,A48,REAL_2:201;
          A51:(qz`2)^2=(q`2/sqrt(1+(q`1/q`2)^2))^2 by A28,A43,EUCLID:56
               .=(q`2)^2/(sqrt(1+(q`1/q`2)^2))^2 by SQUARE_1:69;
          A52:(qz`2)^2>=0 by SQUARE_1:72;
            (q`2)^2>=0 by SQUARE_1:72;
then A53:        (qz`2)^2<=(q`2)^2/1 by A47,A51,REAL_2:201;
          A54:sqrt((((0.REAL 2) - qz)`1)^2+(((0.REAL 2) - qz)`2)^2)
          =sqrt((qz`1)^2+(-qz`2)^2) by A44,A45,SQUARE_1:61
          .=sqrt((qz`1)^2+(qz`2)^2) by SQUARE_1:61;
          A55:(qz`1)^2+(qz`2)^2<=(q`1)^2+(q`2)^2 by A50,A53,REAL_1:55;
            0+0<= (qz`1)^2+(qz`2)^2 by A49,A52,REAL_1:55;
          then sqrt((qz`1)^2+(qz`2)^2) <= sqrt((q`1)^2+(q`2)^2)
                          by A55,SQUARE_1:94;
          then sqrt((((0.REAL 2) - qz)`1)^2+(((0.REAL 2) - qz)`2)^2)<r
                           by A29,A54,AXIOMS:22;
          then |.(0.REAL 2) - qz.|<r by JGRAPH_1:47;
          then dist(u0,pz)<r by JGRAPH_1:45;
         hence thesis by METRIC_1:12;
      end;
     then f.:W1 c= V by A25,XBOOLE_1:1;
   hence ex W being Subset of TOP-REAL 2 st 0.REAL 2 in W
       & W is open & f.:W c= V by A26,A27;
  end;
  then f is continuous by A1,A2,A3,A21,Th13;
 hence thesis;
end;

theorem Th32: Sq_Circ is one-to-one
proof
   let x1,x2 be set;
   assume A1: x1 in dom Sq_Circ & x2 in dom Sq_Circ & Sq_Circ.x1=Sq_Circ.x2;
    then reconsider p1=x1 as Point of TOP-REAL 2;
    reconsider p2=x2 as Point of TOP-REAL 2 by A1;
    set q=p1,p=p2;
    per cases;
    suppose A2:q=0.REAL 2;
      then A3:Sq_Circ.q=0.REAL 2 by Def1;
        now per cases;
      case p=0.REAL 2;
       hence x1=x2 by A2;
      case A4:p<>0.REAL 2 &
          (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
        then Sq_Circ.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|
                                 by Def1;
        then A5:p`1/sqrt(1+(p`2/p`1)^2)=0 & p`2/sqrt(1+(p`2/p`1)^2)=0
                  by A1,A3,EUCLID:56,JGRAPH_2:11;
          (p`2/p`1)^2 >=0 by SQUARE_1:72;
        then 1+(p`2/p`1)^2>=1+0 by REAL_1:55;
        then sqrt(1+(p`2/p`1)^2)>=1 by Th8;
        then A6:sqrt(1+(p`2/p`1)^2)>0 by AXIOMS:22;
        then A7:p`1= 0 *sqrt(1+(p`2/p`1)^2) by A5,XCMPLX_1:88 .=0;
          p`2= 0 *sqrt(1+(p`2/p`1)^2) by A5,A6,XCMPLX_1:88 .=0;
       hence contradiction by A4,A7,EUCLID:57,58;
      case A8:p<>0.REAL 2 &
        not (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
        then Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|
                        by Def1;
        then A9:p`1/sqrt(1+(p`1/p`2)^2)=0 & p`2/sqrt(1+(p`1/p`2)^2)=0
                    by A1,A3,EUCLID:56,JGRAPH_2:11;
          (p`1/p`2)^2 >=0 by SQUARE_1:72;
        then 1+(p`1/p`2)^2>=1+0 by REAL_1:55;
        then sqrt(1+(p`1/p`2)^2)>=1 by Th8;
        then A10:sqrt(1+(p`1/p`2)^2)>0 by AXIOMS:22;
        then A11:p`1= 0 *sqrt(1+(p`1/p`2)^2) by A9,XCMPLX_1:88 .=0;
          p`2= 0 *sqrt(1+(p`1/p`2)^2) by A9,A10,XCMPLX_1:88 .=0;
       hence contradiction by A8,A11;
      end;
     hence x1=x2;
    suppose A12:q<>0.REAL 2 &
          (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
        then A13:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|
                                 by Def1;
        A14: (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`1
         = q`1/sqrt(1+(q`2/q`1)^2) &
         (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`2
         = q`2/sqrt(1+(q`2/q`1)^2) by EUCLID:56;
        A15:1+(q`2/q`1)^2>0 by Lm1;
        then A16:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
        now per cases;
      case p=0.REAL 2;
        then Sq_Circ.p=0.REAL 2 by Def1;
        then A17:q`1/sqrt(1+(q`2/q`1)^2)=0 & q`2/sqrt(1+(q`2/q`1)^2)=0
                  by A1,A13,EUCLID:56,JGRAPH_2:11;
          (q`2/q`1)^2 >=0 by SQUARE_1:72;
        then 1+(q`2/q`1)^2>=1+0 by REAL_1:55;
        then sqrt(1+(q`2/q`1)^2)>=1 by Th8;
        then A18:sqrt(1+(q`2/q`1)^2)>0 by AXIOMS:22;
        then A19:q`1= 0 *sqrt(1+(q`2/q`1)^2) by A17,XCMPLX_1:88 .=0;
          q`2= 0 *sqrt(1+(q`2/q`1)^2) by A17,A18,XCMPLX_1:88 .=0;
       hence contradiction by A12,A19,EUCLID:57,58;
      case A20:p<>0.REAL 2 &
          (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
        then A21:Sq_Circ.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|
                                 by Def1;
        then A22:p`1/sqrt(1+(p`2/p`1)^2)=q`1/sqrt(1+(q`2/q`1)^2) &
        p`2/sqrt(1+(p`2/p`1)^2)=q`2/sqrt(1+(q`2/q`1)^2)
                  by A1,A13,A14,EUCLID:56;
        A23:1+(p`2/p`1)^2>0 by Lm1;
        then A24:sqrt(1+(p`2/p`1)^2)>0 by SQUARE_1:93;
          (p`1)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`1/sqrt(1+(q`2/q`1)^2))^2
                               by A22,SQUARE_1:69;
        then (p`1)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`1)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by SQUARE_1:69;
        then (p`1)^2/(1+(p`2/p`1)^2)=(q`1)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by A23,SQUARE_1:def 4;
        then A25:(p`1)^2/(1+(p`2/p`1)^2)=(q`1)^2/(1+(q`2/q`1)^2)
                               by A15,SQUARE_1:def 4;
          (p`2)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`2/sqrt(1+(q`2/q`1)^2))^2
                               by A22,SQUARE_1:69;
        then (p`2)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by SQUARE_1:69;
        then (p`2)^2/(1+(p`2/p`1)^2)=(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by A23,SQUARE_1:def 4;
        then A26:(p`2)^2/(1+(p`2/p`1)^2)=(q`2)^2/(1+(q`2/q`1)^2)
                               by A15,SQUARE_1:def 4;
          now assume
          A27:p`1=0;
          then p`2=0 by A20;
         hence contradiction by A20,A27,EUCLID:57,58;
        end;
        then A28:(p`1)^2>0 by SQUARE_1:74;
          (p`1)^2/(1+(p`2/p`1)^2)/(p`1)^2=(q`1)^2/(p`1)^2/(1+(q`2/q`1)^2)
                        by A25,XCMPLX_1:48;
        then (p`1)^2/(p`1)^2/(1+(p`2/p`1)^2)=(q`1)^2/(p`1)^2/(1+(q`2/q`1)^2)
                        by XCMPLX_1:48;
        then 1/(1+(p`2/p`1)^2)=(q`1)^2/(p`1)^2/(1+(q`2/q`1)^2)
                        by A28,XCMPLX_1:60;
        then A29:1/(1+(p`2/p`1)^2)*(1+(q`2/q`1)^2)=(q`1)^2/(p`1)^2
                        by A15,XCMPLX_1:88;
          now assume
          A30:q`1=0;
          then q`2=0 by A12;
         hence contradiction by A12,A30,EUCLID:57,58;
        end;
        then A31:(q`1)^2>0 by SQUARE_1:74;
          now per cases;
        case A32:p`2=0;
          then (q`2)^2=0 by A15,A26,SQUARE_1:60,XCMPLX_1:50;
          then A33:q`2=0 by SQUARE_1:73;
          then p=|[q`1,0]|by A1,A13,A21,A32,EUCLID:57,SQUARE_1:60,83;
         hence x1=x2 by A33,EUCLID:57;
        case p`2<>0;
          then A34:(p`2)^2>0 by SQUARE_1:74;
            (p`2)^2/(1+(p`2/p`1)^2)/(p`2)^2=(q`2)^2/(p`2)^2/(1+(q`2/q`1)^2)
                        by A26,XCMPLX_1:48;
          then (p`2)^2/(p`2)^2/(1+(p`2/p`1)^2)=(q`2)^2/(p`2)^2/(1+(q`2/q`1)^2)
                        by XCMPLX_1:48;
          then 1/(1+(p`2/p`1)^2)=(q`2)^2/(p`2)^2/(1+(q`2/q`1)^2)
                        by A34,XCMPLX_1:60;
          then 1/(1+(p`2/p`1)^2)*(1+(q`2/q`1)^2)=(q`2)^2/(p`2)^2
                        by A15,XCMPLX_1:88;
          then (q`1)^2/(q`1)^2/(p`1)^2=(q`2)^2/(p`2)^2/(q`1)^2
                          by A29,XCMPLX_1:48;
          then 1/(p`1)^2=(q`2)^2/(p`2)^2/(q`1)^2 by A31,XCMPLX_1:60;
          then 1/(p`1)^2*(p`2)^2=(p`2)^2*((q`2)^2/(p`2)^2)/(q`1)^2
                          by XCMPLX_1:75;
          then 1/(p`1)^2*(p`2)^2=(q`2)^2/(q`1)^2 by A34,XCMPLX_1:88;
          then (p`2)^2/(p`1)^2=(q`2)^2/(q`1)^2 by XCMPLX_1:100;
          then (p`2/p`1)^2=(q`2)^2/(q`1)^2 by SQUARE_1:69;
          then A35:(1+(p`2/p`1)^2)=(1+(q`2/q`1)^2) by SQUARE_1:69;
          then p`1=q`1/sqrt(1+(q`2/q`1)^2)*sqrt(1+(q`2/q`1)^2)
                        by A22,A24,XCMPLX_1:88;
          then A36:p`1=q`1 by A16,XCMPLX_1:88;
            p`2=q`2/sqrt(1+(q`2/q`1)^2)*sqrt(1+(q`2/q`1)^2)
                        by A22,A24,A35,XCMPLX_1:88;
          then p`2=q`2 by A16,XCMPLX_1:88;
          then p=|[q`1,q`2]|by A36,EUCLID:57;
         hence x1=x2 by EUCLID:57;
        end;
       hence x1=x2;
      case A37:p<>0.REAL 2 &
        not (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
        then A38: p<>0.REAL 2 & p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2
                by JGRAPH_2:23;
          (|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|)`1
         = p`1/sqrt(1+(p`1/p`2)^2) &
         (|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|)`2
         = p`2/sqrt(1+(p`1/p`2)^2) by EUCLID:56;
        then A39:p`1/sqrt(1+(p`1/p`2)^2)=q`1/sqrt(1+(q`2/q`1)^2) &
        p`2/sqrt(1+(p`1/p`2)^2)=q`2/sqrt(1+(q`2/q`1)^2)
                  by A1,A13,A14,A37,Def1;
        A40:1+(p`1/p`2)^2>0 by Lm1;
        then A41:sqrt(1+(p`1/p`2)^2)>0 by SQUARE_1:93;
          (p`1)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`1/sqrt(1+(q`2/q`1)^2))^2
                               by A39,SQUARE_1:69;
        then (p`1)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`1)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by SQUARE_1:69;
        then (p`1)^2/(1+(p`1/p`2)^2)=(q`1)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by A40,SQUARE_1:def 4;
        then A42:(p`1)^2/(1+(p`1/p`2)^2)=(q`1)^2/(1+(q`2/q`1)^2)
                               by A15,SQUARE_1:def 4;
          (p`2)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`2/sqrt(1+(q`2/q`1)^2))^2
                               by A39,SQUARE_1:69;
        then (p`2)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by SQUARE_1:69;
        then (p`2)^2/(1+(p`1/p`2)^2)=(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                               by A40,SQUARE_1:def 4;
        then A43:(p`2)^2/(1+(p`1/p`2)^2)=(q`2)^2/(1+(q`2/q`1)^2)
                               by A15,SQUARE_1:def 4;
          p`2<>0 by A37,A38;
        then A44:(p`2)^2>0 by SQUARE_1:74;
          (p`2)^2/(1+(p`1/p`2)^2)/(p`2)^2=(q`2)^2/(p`2)^2/(1+(q`2/q`1)^2)
                        by A43,XCMPLX_1:48;
        then (p`2)^2/(p`2)^2/(1+(p`1/p`2)^2)=(q`2)^2/(p`2)^2/(1+(q`2/q`1)^2)
                        by XCMPLX_1:48;
        then 1/(1+(p`1/p`2)^2)=(q`2)^2/(p`2)^2/(1+(q`2/q`1)^2)
                        by A44,XCMPLX_1:60;
        then A45:1/(1+(p`1/p`2)^2)*(1+(q`2/q`1)^2)=(q`2)^2/(p`2)^2
                        by A15,XCMPLX_1:88;
        A46:now assume
          A47:q`1=0;
          then q`2=0 by A12;
         hence contradiction by A12,A47,EUCLID:57,58;
        end;
        then A48:(q`1)^2>0 by SQUARE_1:74;
          now per cases;
        case p`1=0;
          then (q`1)^2=0 by A15,A42,SQUARE_1:60,XCMPLX_1:50;
          then A49:q`1=0 by SQUARE_1:73;
          then q`2=0 by A12;
         hence contradiction by A12,A49,EUCLID:57,58;
        case A50:p`1<>0;
          then A51:(p`1)^2>0 by SQUARE_1:74;
            (p`1)^2/(1+(p`1/p`2)^2)/(p`1)^2=(q`1)^2/(p`1)^2/(1+(q`2/q`1)^2)
                        by A42,XCMPLX_1:48;
          then (p`1)^2/(p`1)^2/(1+(p`1/p`2)^2)=(q`1)^2/(p`1)^2/(1+(q`2/q`1)^2)
                        by XCMPLX_1:48;
          then 1/(1+(p`1/p`2)^2)=(q`1)^2/(p`1)^2/(1+(q`2/q`1)^2)
                        by A51,XCMPLX_1:60;
          then 1/(1+(p`1/p`2)^2)*(1+(q`2/q`1)^2)=(q`1)^2/(p`1)^2
                        by A15,XCMPLX_1:88;
          then (q`1)^2/(q`1)^2/(p`1)^2=(q`2)^2/(p`2)^2/(q`1)^2 by A45,XCMPLX_1:
48;
          then 1/(p`1)^2=(q`2)^2/(p`2)^2/(q`1)^2 by A48,XCMPLX_1:60;
          then 1/(p`1)^2*(p`2)^2=(p`2)^2*((q`2)^2/(p`2)^2)/(q`1)^2
                        by XCMPLX_1:75;
          then 1/(p`1)^2*(p`2)^2=(q`2)^2/(q`1)^2 by A44,XCMPLX_1:88;
          then (p`2)^2/(p`1)^2=(q`2)^2/(q`1)^2 by XCMPLX_1:100;
          then (p`2/p`1)^2=(q`2)^2/(q`1)^2 by SQUARE_1:69;
           then A52:(p`2/p`1)^2=(q`2/q`1)^2 by SQUARE_1:69;
           set a=q`2/q`1;
           A53:p`2/p`1*p`1=a*p`1 or p`2/p`1*p`1=(-a)*p`1 by A52,Th1;
           A54:now per cases by A50,A53,XCMPLX_1:88;
           case A55: p`2=a*p`1;
               now per cases by A50;
             case p`1>0;
               then p`1/p`1<= a*p`1/p`1 & (-(a*p`1))/p`1<=p`1/p`1 or
                  p`1/p`1>=(a*p`1)/p`1 & p`1/p`1<=(-(a*p`1))/p`1
                                      by A38,A55,REAL_1:73;
               then A56:1<= a*p`1/p`1 & (-(a*p`1))/p`1<=1 or
               1>=(a*p`1)/p`1 & 1<=(-(a*p`1))/p`1 by A50,XCMPLX_1:60;
                 (a*p`1)/p`1=a by A50,XCMPLX_1:90;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A56,XCMPLX_1:188;
             case p`1<0;
               then p`1/p`1>= a*p`1/p`1 & (-(a*p`1))/p`1>=p`1/p`1 or
                  p`1/p`1<=(a*p`1)/p`1 & p`1/p`1>=(-(a*p`1))/p`1
                                      by A38,A55,REAL_1:74;
               then A57:1>= a*p`1/p`1 & (-(a*p`1))/p`1>=1 or
               1<=(a*p`1)/p`1 & 1>=(-(a*p`1))/p`1 by A50,XCMPLX_1:60;
                (a*p`1)/p`1=a by A50,XCMPLX_1:90;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A57,XCMPLX_1:188;
             end;
             then 1<=a & -a<=1 or 1>=a & -1>=--a by REAL_1:50;
            hence 1<=a or -1>=a;
           case A58: p`2=(-a)*p`1;
               now per cases by A50;
             case p`1>0;
               then p`1/p`1<= (-a)*p`1/p`1 & (-((-a)*p`1))/p`1<=p`1/p`1 or
                  p`1/p`1>=((-a)*p`1)/p`1 & p`1/p`1<=(-((-a)*p`1))/p`1
                                      by A38,A58,REAL_1:73;
               then A59:1<= (-a)*p`1/p`1 & (-((-a)*p`1))/p`1<=1 or
               1>=((-a)*p`1)/p`1 & 1<=(-((-a)*p`1))/p`1 by A50,XCMPLX_1:60;
               A60:((-a)*p`1)/p`1=(-a) by A50,XCMPLX_1:90;
                 1<= (-a) & -(((-a)*p`1)/p`1)<=1 or
               1>=(-a) & 1<=-(((-a)*p`1)/p`1) by A50,A59,XCMPLX_1:90,188;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A60;
             case p`1<0;
               then p`1/p`1>= (-a)*p`1/p`1 & (-((-a)*p`1))/p`1>=p`1/p`1 or
                  p`1/p`1<=((-a)*p`1)/p`1 & p`1/p`1>=(-((-a)*p`1))/p`1
                                      by A38,A58,REAL_1:74;
               then A61:1>= (-a)*p`1/p`1 & (-((-a)*p`1))/p`1>=1 or
               1<=((-a)*p`1)/p`1 & 1>=(-((-a)*p`1))/p`1 by A50,XCMPLX_1:60;
               A62:((-a)*p`1)/p`1=(-a) by A50,XCMPLX_1:90;
                 1>= (-a) & -(((-a)*p`1)/p`1)>=1 or
               1<=(-a) & 1>=-(((-a)*p`1)/p`1) by A50,A61,XCMPLX_1:90,188;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A62;
             end;
             then 1<=a & -a<=1 or 1>=a & -1>=--a by REAL_1:50;
            hence 1<=a or -1>=a;
           end;
           A63:q`1*a<=q`1 & -q`1<=q`1*a or q`1*a>=q`1 & q`1*a<=-q`1
             by A12,A46,XCMPLX_1:88;
           A64:now per cases by A46;
           case A65:q`1>0;
             then a*q`1/q`1<=q`1/q`1 & (-q`1)/q`1<=a*q`1/q`1
              or a*q`1/q`1>=q`1/q`1 & a*q`1/q`1<=(-q`1)/q`1 by A63,REAL_1:73;
             then A66:a<=q`1/q`1 & (-q`1)/q`1<=a
              or a>=q`1/q`1 & a<=(-q`1)/q`1 by A65,XCMPLX_1:90;
               q`1/q`1=1 by A65,XCMPLX_1:60;
            hence a<=1 & -1<=a or a>=1 & a<=-1 by A66,XCMPLX_1:188;
           case A67:q`1<0;
             then A68:a*q`1/q`1>=q`1/q`1 & (-q`1)/q`1>=a*q`1/q`1
              or a*q`1/q`1<=q`1/q`1 & a*q`1/q`1>=(-q`1)/q`1 by A63,REAL_1:74;
             A69:q`1/q`1=1 by A67,XCMPLX_1:60;
               (-q`1)/q`1=-1 by A67,XCMPLX_1:198;
            hence a<=1 & -1<=a or a>=1 & a<=-1 by A67,A68,A69,XCMPLX_1:90
;
           end;
A70:      now per cases by A54,A64,AXIOMS:21,22;
           case a=1;
             then (p`2)^2/(p`1)^2=1 by A52,SQUARE_1:59,69;
             then A71:(p`2)^2=(p`1)^2 by XCMPLX_1:58;
               (p`1/p`2)^2=(p`1)^2/(p`2)^2 by SQUARE_1:69;
            hence (p`1/p`2)^2=(q`2/q`1)^2 by A52,A71,SQUARE_1:69;
           case a=-1; then a^2=1 by SQUARE_1:59,61;
             then (p`2)^2/(p`1)^2=1 by A52,SQUARE_1:69;
             then A72:(p`2)^2=(p`1)^2 by XCMPLX_1:58;
               (p`1/p`2)^2=(p`1)^2/(p`2)^2 by SQUARE_1:69;
            hence (p`1/p`2)^2=(q`2/q`1)^2 by A52,A72,SQUARE_1:69;
           end;
          then p`1=q`1/sqrt(1+(q`2/q`1)^2)*sqrt(1+(q`2/q`1)^2)
                        by A39,A41,XCMPLX_1:88;
          then A73:p`1=q`1 by A16,XCMPLX_1:88;
            p`2=q`2/sqrt(1+(q`2/q`1)^2)*sqrt(1+(q`2/q`1)^2)
                        by A39,A41,A70,XCMPLX_1:88;
          then p`2=q`2 by A16,XCMPLX_1:88;
          then p=|[q`1,q`2]| by A73,EUCLID:57;
         hence x1=x2 by EUCLID:57;
        end;
       hence x1=x2;
      end;
     hence x1=x2;
    suppose A74:q<>0.REAL 2 &
         not (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
       then A75:Sq_Circ.q=|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|
                        by Def1;
        A76: (|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|)`1
         = q`1/sqrt(1+(q`1/q`2)^2) &
         (|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|)`2
         = q`2/sqrt(1+(q`1/q`2)^2) by EUCLID:56;
        A77:1+(q`1/q`2)^2>0 by Lm1;
        then A78:sqrt(1+(q`1/q`2)^2)>0 by SQUARE_1:93;
        A79: (q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 & q`1<=-q`2)
                      by A74,JGRAPH_2:23;
        now per cases;
      case p=0.REAL 2;
        then Sq_Circ.p=0.REAL 2 by Def1;
        then A80:q`1/sqrt(1+(q`1/q`2)^2)=0 & q`2/sqrt(1+(q`1/q`2)^2)=0
                  by A1,A75,EUCLID:56,JGRAPH_2:11;
          (q`1/q`2)^2 >=0 by SQUARE_1:72;
        then 1+(q`1/q`2)^2>=1+0 by REAL_1:55;
        then sqrt(1+(q`1/q`2)^2)>=1 by Th8;
        then A81:sqrt(1+(q`1/q`2)^2)>0 by AXIOMS:22;
        then A82:q`1= 0 *sqrt(1+(q`1/q`2)^2) by A80,XCMPLX_1:88 .=0;
          q`2= 0 *sqrt(1+(q`1/q`2)^2) by A80,A81,XCMPLX_1:88 .=0;
       hence contradiction by A74,A82;
      case A83:p<>0.REAL 2 &
          (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
        then Sq_Circ.p=|[p`1/sqrt(1+(p`2/p`1)^2),p`2/sqrt(1+(p`2/p`1)^2)]|
                                 by Def1;
        then A84:p`1/sqrt(1+(p`2/p`1)^2)=q`1/sqrt(1+(q`1/q`2)^2) &
        p`2/sqrt(1+(p`2/p`1)^2)=q`2/sqrt(1+(q`1/q`2)^2)
                  by A1,A75,A76,EUCLID:56;
        A85:1+(p`2/p`1)^2>0 by Lm1;
        then A86:sqrt(1+(p`2/p`1)^2)>0 by SQUARE_1:93;
          (p`1)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`1/sqrt(1+(q`1/q`2)^2))^2
                               by A84,SQUARE_1:69;
        then (p`1)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`1)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by SQUARE_1:69;
        then (p`1)^2/(1+(p`2/p`1)^2)=(q`1)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by A85,SQUARE_1:def 4;
        then A87:(p`1)^2/(1+(p`2/p`1)^2)=(q`1)^2/(1+(q`1/q`2)^2)
                               by A77,SQUARE_1:def 4;
          (p`2)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`2/sqrt(1+(q`1/q`2)^2))^2
                               by A84,SQUARE_1:69;
        then (p`2)^2/(sqrt(1+(p`2/p`1)^2))^2=(q`2)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by SQUARE_1:69;
        then (p`2)^2/(1+(p`2/p`1)^2)=(q`2)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by A85,SQUARE_1:def 4;
        then A88:(p`2)^2/(1+(p`2/p`1)^2)=(q`2)^2/(1+(q`1/q`2)^2)
                               by A77,SQUARE_1:def 4;
          now assume
          A89:p`1=0;
          then p`2=0 by A83;
         hence contradiction by A83,A89,EUCLID:57,58;
        end;
        then A90:(p`1)^2>0 by SQUARE_1:74;
          (p`1)^2/(1+(p`2/p`1)^2)/(p`1)^2=(q`1)^2/(p`1)^2/(1+(q`1/q`2)^2)
                        by A87,XCMPLX_1:48;
        then (p`1)^2/(p`1)^2/(1+(p`2/p`1)^2)=(q`1)^2/(p`1)^2/(1+(q`1/q`2)^2)
                        by XCMPLX_1:48;
        then 1/(1+(p`2/p`1)^2)=(q`1)^2/(p`1)^2/(1+(q`1/q`2)^2)
                        by A90,XCMPLX_1:60;
    then A91:1/(1+(p`2/p`1)^2)*(1+(q`1/q`2)^2)=(q`1)^2/(p`1)^2 by A77,XCMPLX_1:
88
;
        A92: q`2<>0 by A74,A79;
        then A93:(q`2)^2>0 by SQUARE_1:74;
          now per cases;
        case p`2=0;
          then (q`2)^2=0 by A77,A88,SQUARE_1:60,XCMPLX_1:50;
          then q`2=0 by SQUARE_1:73;
         hence contradiction by A74,A79;
        case A94:p`2<>0;
          then A95:(p`2)^2>0 by SQUARE_1:74;
            (p`2)^2/(1+(p`2/p`1)^2)/(p`2)^2=(q`2)^2/(p`2)^2/(1+(q`1/q`2)^2)
                        by A88,XCMPLX_1:48;
          then (p`2)^2/(p`2)^2/(1+(p`2/p`1)^2)=(q`2)^2/(p`2)^2/(1+(q`1/q`2)^2)
                        by XCMPLX_1:48;
          then 1/(1+(p`2/p`1)^2)=(q`2)^2/(p`2)^2/(1+(q`1/q`2)^2)
                        by A95,XCMPLX_1:60;
          then 1/(1+(p`2/p`1)^2)*(1+(q`1/q`2)^2)=(q`2)^2/(p`2)^2
                        by A77,XCMPLX_1:88;
          then (q`2)^2/(q`2)^2/(p`2)^2=(q`1)^2/(p`1)^2/(q`2)^2
                        by A91,XCMPLX_1:48;
          then 1/(p`2)^2=(q`1)^2/(p`1)^2/(q`2)^2 by A93,XCMPLX_1:60;
          then 1/(p`2)^2*(p`1)^2=(p`1)^2*((q`1)^2/(p`1)^2)/(q`2)^2
                        by XCMPLX_1:75;
          then 1/(p`2)^2*(p`1)^2=(q`1)^2/(q`2)^2 by A90,XCMPLX_1:88;
          then (p`1)^2/(p`2)^2=(q`1)^2/(q`2)^2 by XCMPLX_1:100;
          then (p`1/p`2)^2=(q`1)^2/(q`2)^2 by SQUARE_1:69;
           then A96:(p`1/p`2)^2=(q`1/q`2)^2 by SQUARE_1:69;
           then A97:p`1/p`2=q`1/q`2 or p`1/p`2=-q`1/q`2 by Th1;
           set a=q`1/q`2;
           A98:now per cases by A94,A97,XCMPLX_1:88;
           case A99: p`1=a*p`2;
               now per cases by A94;
             case p`2>0;
               then p`2/p`2<= a*p`2/p`2 & (-(a*p`2))/p`2<=p`2/p`2 or
                  p`2/p`2>=(a*p`2)/p`2 & p`2/p`2<=(-(a*p`2))/p`2
                                      by A83,A99,REAL_1:73;
               then A100:1<= a*p`2/p`2 & (-(a*p`2))/p`2<=1 or
               1>=(a*p`2)/p`2 & 1<=(-(a*p`2))/p`2 by A94,XCMPLX_1:60;
                 (a*p`2)/p`2=a by A94,XCMPLX_1:90;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A100,XCMPLX_1:188;
             case p`2<0;
               then p`2/p`2>= a*p`2/p`2 & (-(a*p`2))/p`2>=p`2/p`2 or
                  p`2/p`2<=(a*p`2)/p`2 & p`2/p`2>=(-(a*p`2))/p`2
                                      by A83,A99,REAL_1:74;
               then A101:1>= a*p`2/p`2 & (-(a*p`2))/p`2>=1 or
               1<=(a*p`2)/p`2 & 1>=(-(a*p`2))/p`2 by A94,XCMPLX_1:60;
                 (a*p`2)/p`2=a by A94,XCMPLX_1:90;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A101,XCMPLX_1:188;
             end;
             then 1<=a & -a<=1 or 1>=a & -1>=--a by REAL_1:50;
            hence 1<=a or -1>=a;
           case A102: p`1=(-a)*p`2;
               now per cases by A94;
             case p`2>0;
               then p`2/p`2<= (-a)*p`2/p`2 & (-((-a)*p`2))/p`2<=p`2/p`2 or
                  p`2/p`2>=((-a)*p`2)/p`2 & p`2/p`2<=(-((-a)*p`2))/p`2
                                      by A83,A102,REAL_1:73;
               then A103:1<= (-a)*p`2/p`2 & (-((-a)*p`2))/p`2<=1 or
               1>=((-a)*p`2)/p`2 & 1<=(-((-a)*p`2))/p`2 by A94,XCMPLX_1:60;
               A104:((-a)*p`2)/p`2=(-a) by A94,XCMPLX_1:90;
                 1<= (-a) & -(((-a)*p`2)/p`2)<=1 or
               1>=(-a) & 1<=-(((-a)*p`2)/p`2) by A94,A103,XCMPLX_1:90,188;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A104;
             case p`2<0;
               then p`2/p`2>= (-a)*p`2/p`2 & (-((-a)*p`2))/p`2>=p`2/p`2 or
                  p`2/p`2<=((-a)*p`2)/p`2 & p`2/p`2>=(-((-a)*p`2))/p`2
                                      by A83,A102,REAL_1:74;
               then A105:1>= (-a)*p`2/p`2 & (-((-a)*p`2))/p`2>=1 or
               1<=((-a)*p`2)/p`2 & 1>=(-((-a)*p`2))/p`2 by A94,XCMPLX_1:60;
               A106:((-a)*p`2)/p`2=(-a) by A94,XCMPLX_1:90;
                 1>= -a & -(((-a)*p`2)/p`2)>=1 or
               1<=-a & 1>=-(((-a)*p`2)/p`2) by A94,A105,XCMPLX_1:90,188;
              hence 1<=a & -a<=1 or 1>=a & 1<=-a by A106;
             end;
             then 1<=a & -a<=1 or 1>=a & -1>=--a by REAL_1:50;
            hence 1<=a or -1>=a;
           end;
           A107:q`2*a<=q`2 & -q`2<=q`2*a or q`2*a>=q`2 & q`2*a<=-q`2
                                    by A79,A92,XCMPLX_1:88;
           A108:now per cases by A92;
           case A109:q`2>0;
             then A110:a*q`2/q`2<=q`2/q`2 & (-q`2)/q`2<=a*q`2/q`2
              or a*q`2/q`2>=q`2/q`2 & a*q`2/q`2<=(-q`2)/q`2 by A107,REAL_1:73;
             A111:q`2/q`2=1 by A109,XCMPLX_1:60;
               (-q`2)/q`2=-1 by A109,XCMPLX_1:198;
            hence a<=1 & -1<=a or a>=1 & a<=-1 by A109,A110,A111,XCMPLX_1:90;
           case A112:q`2<0;
             then a*q`2/q`2>=q`2/q`2 & (-q`2)/q`2>=a*q`2/q`2
              or a*q`2/q`2<=q`2/q`2 & a*q`2/q`2>=(-q`2)/q`2 by A107,REAL_1:74;
             then a>=q`2/q`2 & (-q`2)/q`2>=a
              or a<=q`2/q`2 & a>=(-q`2)/q`2 by A112,XCMPLX_1:90;
            hence a<=1 & -1<=a or a>=1 & a<=-1 by A112,XCMPLX_1:60,198;
           end;
A113:      now per cases by A98,A108,AXIOMS:21,22;
           case a=1;
             then (p`1)^2/(p`2)^2=1 by A96,SQUARE_1:59,69;
             then A114:(p`1)^2=(p`2)^2 by XCMPLX_1:58;
               (p`2/p`1)^2=(p`2)^2/(p`1)^2 by SQUARE_1:69;
            hence (p`2/p`1)^2=(q`1/q`2)^2 by A96,A114,SQUARE_1:69;
           case a=-1; then a^2=1 by SQUARE_1:59,61;
             then (p`1)^2/(p`2)^2=1 by A96,SQUARE_1:69;
             then A115:(p`1)^2=(p`2)^2 by XCMPLX_1:58;
               (p`2/p`1)^2=(p`2)^2/(p`1)^2 by SQUARE_1:69;
            hence (p`2/p`1)^2=(q`1/q`2)^2 by A96,A115,SQUARE_1:69;
           end;
          then p`2=q`2/sqrt(1+(q`1/q`2)^2)*sqrt(1+(q`1/q`2)^2)
                        by A84,A86,XCMPLX_1:88;
          then A116:p`2=q`2 by A78,XCMPLX_1:88;
            p`1=q`1/sqrt(1+(q`1/q`2)^2)*sqrt(1+(q`1/q`2)^2)
                        by A84,A86,A113,XCMPLX_1:88;
          then p`1=q`1 by A78,XCMPLX_1:88;
          then p=|[q`1,q`2]|by A116,EUCLID:57;
         hence x1=x2 by EUCLID:57;
        end;
       hence x1=x2;
      case A117:p<>0.REAL 2 &
         not (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
         then A118: (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) by JGRAPH_2:
23;
        A119:Sq_Circ.p=|[p`1/sqrt(1+(p`1/p`2)^2),p`2/sqrt(1+(p`1/p`2)^2)]|
                                 by A117,Def1;
        then A120:p`2/sqrt(1+(p`1/p`2)^2)=q`2/sqrt(1+(q`1/q`2)^2) &
        p`1/sqrt(1+(p`1/p`2)^2)=q`1/sqrt(1+(q`1/q`2)^2)
                  by A1,A75,A76,EUCLID:56;
        A121:1+(p`1/p`2)^2>0 by Lm1;
        then A122:sqrt(1+(p`1/p`2)^2)>0 by SQUARE_1:93;
          (p`2)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`2/sqrt(1+(q`1/q`2)^2))^2
                               by A120,SQUARE_1:69;
        then (p`2)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`2)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by SQUARE_1:69;
        then (p`2)^2/(1+(p`1/p`2)^2)=(q`2)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by A121,SQUARE_1:def 4;
        then A123:(p`2)^2/(1+(p`1/p`2)^2)=(q`2)^2/(1+(q`1/q`2)^2)
                               by A77,SQUARE_1:def 4;
          (p`1)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`1/sqrt(1+(q`1/q`2)^2))^2
                               by A120,SQUARE_1:69;
        then (p`1)^2/(sqrt(1+(p`1/p`2)^2))^2=(q`1)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by SQUARE_1:69;
        then (p`1)^2/(1+(p`1/p`2)^2)=(q`1)^2/(sqrt(1+(q`1/q`2)^2))^2
                               by A121,SQUARE_1:def 4;
        then A124:(p`1)^2/(1+(p`1/p`2)^2)=(q`1)^2/(1+(q`1/q`2)^2)
                               by A77,SQUARE_1:def 4;
          p`2<>0 by A117,A118;
        then A125:(p`2)^2>0 by SQUARE_1:74;
          (p`2)^2/(1+(p`1/p`2)^2)/(p`2)^2=(q`2)^2/(p`2)^2/(1+(q`1/q`2)^2)
                        by A123,XCMPLX_1:48;
        then (p`2)^2/(p`2)^2/(1+(p`1/p`2)^2)=(q`2)^2/(p`2)^2/(1+(q`1/q`2)^2)
                        by XCMPLX_1:48;
        then 1/(1+(p`1/p`2)^2)=(q`2)^2/(p`2)^2/(1+(q`1/q`2)^2)
                        by A125,XCMPLX_1:60;
        then A126:1/(1+(p`1/p`2)^2)*(1+(q`1/q`2)^2)=(q`2)^2/(p`2)^2
                        by A77,XCMPLX_1:88;
          q`2<>0 by A74,A79;
        then A127:(q`2)^2>0 by SQUARE_1:74;
          now per cases;
        case A128:p`1=0;
          then (q`1)^2=0 by A77,A124,SQUARE_1:60,XCMPLX_1:50;
          then A129:q`1=0 by SQUARE_1:73;
          then p=|[0,q`2]|by A1,A75,A119,A128,EUCLID:57,SQUARE_1:60,83;
         hence x1=x2 by A129,EUCLID:57;
        case p`1<>0;
          then A130:(p`1)^2>0 by SQUARE_1:74;
            (p`1)^2/(1+(p`1/p`2)^2)/(p`1)^2=(q`1)^2/(p`1)^2/(1+(q`1/q`2)^2)
                        by A124,XCMPLX_1:48;
          then (p`1)^2/(p`1)^2/(1+(p`1/p`2)^2)=(q`1)^2/(p`1)^2/(1+(q`1/q`2)^2)
                        by XCMPLX_1:48;
          then 1/(1+(p`1/p`2)^2)=(q`1)^2/(p`1)^2/(1+(q`1/q`2)^2)
                        by A130,XCMPLX_1:60;
          then 1/(1+(p`1/p`2)^2)*(1+(q`1/q`2)^2)=(q`1)^2/(p`1)^2
                        by A77,XCMPLX_1:88;
          then (q`2)^2/(q`2)^2/(p`2)^2=(q`1)^2/(p`1)^2/(q`2)^2
                        by A126,XCMPLX_1:48;
          then 1/(p`2)^2=(q`1)^2/(p`1)^2/(q`2)^2 by A127,XCMPLX_1:60;
          then 1/(p`2)^2*(p`1)^2=(p`1)^2*((q`1)^2/(p`1)^2)/(q`2)^2
                        by XCMPLX_1:75;
          then 1/(p`2)^2*(p`1)^2=(q`1)^2/(q`2)^2 by A130,XCMPLX_1:88;
          then (p`1)^2/(p`2)^2=(q`1)^2/(q`2)^2 by XCMPLX_1:100;
          then (p`1/p`2)^2=(q`1)^2/(q`2)^2 by SQUARE_1:69;
          then A131:(1+(p`1/p`2)^2)=(1+(q`1/q`2)^2) by SQUARE_1:69;
          then p`2=q`2/sqrt(1+(q`1/q`2)^2)*sqrt(1+(q`1/q`2)^2)
                        by A120,A122,XCMPLX_1:88;
          then A132:p`2=q`2 by A78,XCMPLX_1:88;
            p`1=q`1/sqrt(1+(q`1/q`2)^2)*sqrt(1+(q`1/q`2)^2)
                        by A120,A122,A131,XCMPLX_1:88;
          then p`1=q`1 by A78,XCMPLX_1:88;
          then p=|[q`1,q`2]|by A132,EUCLID:57;
         hence x1=x2 by EUCLID:57;
        end;
       hence x1=x2;
    end;
   hence x1=x2;
end;

definition
  cluster Sq_Circ -> one-to-one;
  coherence by Th32;
end;

theorem Th33: for Kb,Cb being Subset of TOP-REAL 2 st
 Kb={q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1}&
 Cb={p2 where p2 is Point of TOP-REAL 2: |.p2.|=1} holds Sq_Circ.:Kb=Cb
 proof let Kb,Cb be Subset of TOP-REAL 2;
  assume
   A1:Kb={q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1}&
      Cb={p2 where p2 is Point of TOP-REAL 2: |.p2.|=1};
   thus Sq_Circ.:Kb c= Cb
    proof let y be set;assume y in Sq_Circ.:Kb;
      then consider x being set such that
      A2: x in dom Sq_Circ & x in Kb & y=Sq_Circ.x
                   by FUNCT_1:def 12;
      consider q being Point of TOP-REAL 2 such that
      A3:q=x &( -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1)
                        by A1,A2;
        now per cases;
      case q=0.REAL 2;
       hence contradiction by A3,JGRAPH_2:11;
      case A4:q<>0.REAL 2 &
          (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
        then A5:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|
                                 by Def1;
        A6: (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`1
         = q`1/sqrt(1+(q`2/q`1)^2) &
         (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`2
         = q`2/sqrt(1+(q`2/q`1)^2) by EUCLID:56;
        A7:1+(q`2)^2>0 by Lm1;
          now per cases by A3;
        case -1=q`1 & -1<=q`2 & q`2<=1;
           then A8: |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|^2
          =((-1)/sqrt(1+(q`2/(-1))^2))^2+(q`2/sqrt(1+(q`2/(-1))^2))^2
                        by A6,JGRAPH_1:46
          .=(-1)^2/(sqrt(1+(q`2/(-1))^2))^2+(q`2/sqrt(1+(q`2/(-1))^2))^2
                        by SQUARE_1:69
          .=(-1)^2/(sqrt(1+(q`2/(-1))^2))^2+(q`2)^2/(sqrt(1+(q`2/(-1))^2))^2
                        by SQUARE_1:69
          .=1/(sqrt(1+(q`2/(-1))^2))^2+(q`2)^2/(sqrt(1+(q`2/(-1))^2))^2
                        by SQUARE_1:59,61
          .=1/(sqrt(1+(-q`2)^2))^2+(q`2)^2/(sqrt(1+(q`2/(-1))^2))^2
            by XCMPLX_1:194
          .=1/(sqrt(1+(-q`2)^2))^2+(q`2)^2/(sqrt(1+(-q`2)^2))^2 by XCMPLX_1:194
          .=1/(sqrt(1+(q`2)^2))^2+(q`2)^2/(sqrt(1+(-q`2)^2))^2 by SQUARE_1:61
          .=1/(sqrt(1+(q`2)^2))^2+(q`2)^2/(sqrt(1+(q`2)^2))^2 by SQUARE_1:61
          .=1/(1+(q`2)^2)+(q`2)^2/(sqrt(1+(q`2)^2))^2 by A7,SQUARE_1:def 4
          .=1/(1+(q`2)^2)+(q`2)^2/(1+(q`2)^2) by A7,SQUARE_1:def 4
          .=(1+(q`2)^2)/(1+(q`2)^2) by XCMPLX_1:63
          .=1 by A7,XCMPLX_1:60;
            0<=|.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|
                               by TOPRNS_1:26;
          then |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|=1
                               by A8,SQUARE_1:83,89;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A2,A3,A5;
        case q`1=1 & -1<=q`2 & q`2<=1;
           then A9: |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|^2
          =(1/sqrt(1+(q`2/(1))^2))^2+(q`2/sqrt(1+(q`2/(1))^2))^2
                        by A6,JGRAPH_1:46
          .=1^2/(sqrt(1+(q`2/(1))^2))^2+(q`2/sqrt(1+(q`2/(1))^2))^2
                        by SQUARE_1:69
          .=1/(sqrt(1+(q`2/(1))^2))^2+(q`2)^2/(sqrt(1+(q`2/(1))^2))^2
                        by SQUARE_1:59,69
          .=1/(1+(q`2)^2)+(q`2)^2/(sqrt(1+(q`2)^2))^2
                        by A7,SQUARE_1:def 4
          .=1/(1+(q`2)^2)+(q`2)^2/(1+(q`2)^2) by A7,SQUARE_1:def 4
          .=(1+(q`2)^2)/(1+(q`2)^2) by XCMPLX_1:63
          .=1 by A7,XCMPLX_1:60;
            0<=|.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|
                               by TOPRNS_1:26;
          then |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|=1
                               by A9,SQUARE_1:83,89;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A2,A3,A5;
        case A10: -1=q`2 & -1<=q`1 & q`1<=1;
          then (-1<=q`1 & q`1>=1 or -1>=q`1 & 1>=q`1) by A4,REAL_1:50;
           then q`1=1 or q`1=-1 by A10,AXIOMS:21;
           then A11:(q`1)^2=1 by SQUARE_1:59,61;
           A12: |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|^2
          =((q`1)/sqrt(1+((-1)/(q`1))^2))^2+((-1)/sqrt(1+((-1)/(q`1))^2))^2
                        by A6,A10,JGRAPH_1:46
         .=((q`1)/sqrt(1+((-1)/(q`1))^2))^2+(-1)^2/(sqrt(1+((-1)/(q`1))^2))^2
                        by SQUARE_1:69
       .=(q`1)^2/(sqrt(1+((-1)/(q`1))^2))^2+(-1)^2/(sqrt(1+((-1)/(q`1))^2))^2
                        by SQUARE_1:69
          .=(q`1)^2/(sqrt(1+((-1)/(q`1))^2))^2+1/(sqrt(1+((-1)/(q`1))^2))^2
                        by SQUARE_1:59,61
          .=(q`1)^2/(sqrt(1+(-1)^2/(q`1)^2))^2+1/(sqrt(1+((-1)/(q`1))^2))^2
                        by SQUARE_1:69
          .=(q`1)^2/(sqrt(1+(-1)^2/(q`1)^2))^2+1/(sqrt(1+(-1)^2/(q`1)^2))^2
                        by SQUARE_1:69
          .=(q`1)^2/(sqrt(1+(1)^2/(q`1)^2))^2+1/(sqrt(1+(-1)^2/(q`1)^2))^2
                        by SQUARE_1:61
          .=1/(sqrt(1+1/1))^2+1/(sqrt(1+1/1))^2 by A11,SQUARE_1:59,61
          .=1/2+1/(sqrt(2))^2 by SQUARE_1:def 4
          .=1/2+1/2 by SQUARE_1:def 4
          .=1;
            0<=|.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|
                               by TOPRNS_1:26;
          then |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|=1
                               by A12,SQUARE_1:83,89;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A2,A3,A5;
        case A13: 1=q`2 & -1<=q`1 & q`1<=1;
          then (1<=q`1 & q`1>=-1 or 1>=q`1 & -1>=q`1) by A4,REAL_2:109;
           then q`1=1 or q`1=-1 by A13,AXIOMS:21;
           then A14:(q`1)^2=1 by SQUARE_1:59,61;
           A15: |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|^2
          =((q`1)/sqrt(1+((1)/(q`1))^2))^2+((1)/sqrt(1+((1)/(q`1))^2))^2
                        by A6,A13,JGRAPH_1:46
         .=((q`1)/sqrt(1+((1)/(q`1))^2))^2+(1)^2/(sqrt(1+((1)/(q`1))^2))^2
                        by SQUARE_1:69
          .=(q`1)^2/(sqrt(1+((1)/(q`1))^2))^2+1/(sqrt(1+((1)/(q`1))^2))^2
                        by SQUARE_1:59,69
          .=(q`1)^2/(sqrt(1+(1)^2/(q`1)^2))^2+1/(sqrt(1+((1)/(q`1))^2))^2
                        by SQUARE_1:69
          .=1/(sqrt(1+1/1))^2+1/(sqrt(1+1/1))^2 by A14,SQUARE_1:59,69
          .=1/2+1/(sqrt(2))^2 by SQUARE_1:def 4
          .=1/2+1/2 by SQUARE_1:def 4
          .=1;
            0<=|.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|
                               by TOPRNS_1:26;
          then |.(|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|).|=1
                               by A15,SQUARE_1:83,89;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A2,A3,A5;
        end;
       hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1;
      case A16:q<>0.REAL 2 &
        not(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
        then A17:Sq_Circ.q=|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|
                                 by Def1;
        A18: (|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|)`1
         = q`1/sqrt(1+(q`1/q`2)^2) &
         (|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|)`2
         = q`2/sqrt(1+(q`1/q`2)^2) by EUCLID:56;
        A19:1+(q`1)^2>0 by Lm1;
          now per cases by A3;
        case -1=q`2 & -1<=q`1 & q`1<=1;
           then A20: |.(|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|).|
^2
          =(q`1/sqrt(1+(q`1/(-1))^2))^2+((-1)/sqrt(1+(q`1/(-1))^2))^2
                        by A18,JGRAPH_1:46
          .=(-1)^2/(sqrt(1+(q`1/(-1))^2))^2+(q`1/sqrt(1+(q`1/(-1))^2))^2
                        by SQUARE_1:69
          .=(-1)^2/(sqrt(1+(q`1/(-1))^2))^2+(q`1)^2/(sqrt(1+(q`1/(-1))^2))^2
                        by SQUARE_1:69
          .=1/(sqrt(1+(q`1/(-1))^2))^2+(q`1)^2/(sqrt(1+(q`1/(-1))^2))^2
                        by SQUARE_1:59,61
          .=1/(sqrt(1+(-q`1)^2))^2+(q`1)^2/(sqrt(1+(q`1/(-1))^2))^2
                        by XCMPLX_1:194
          .=1/(sqrt(1+(-q`1)^2))^2+(q`1)^2/(sqrt(1+(-q`1)^2))^2 by XCMPLX_1:194
          .=1/(sqrt(1+(q`1)^2))^2+(q`1)^2/(sqrt(1+(-q`1)^2))^2 by SQUARE_1:61
          .=1/(sqrt(1+(q`1)^2))^2+(q`1)^2/(sqrt(1+(q`1)^2))^2 by SQUARE_1:61
          .=1/(1+(q`1)^2)+(q`1)^2/(sqrt(1+(q`1)^2))^2 by A19,SQUARE_1:def 4
          .=1/(1+(q`1)^2)+(q`1)^2/(1+(q`1)^2) by A19,SQUARE_1:def 4
          .=(1+(q`1)^2)/(1+(q`1)^2) by XCMPLX_1:63
          .=1 by A19,XCMPLX_1:60;
            0<=|.(|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|).|
                               by TOPRNS_1:26;
          then |.(|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|).|=1
                               by A20,SQUARE_1:83,89;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A2,A3,A17;
        case q`2=1 & -1<=q`1 & q`1<=1;
           then A21: |.(|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|).|
^2
          =((1)/sqrt(1+(q`1/(1))^2))^2+(q`1/sqrt(1+(q`1/(1))^2))^2
                        by A18,JGRAPH_1:46
          .=1^2/(sqrt(1+(q`1/(1))^2))^2+(q`1/sqrt(1+(q`1/(1))^2))^2
                        by SQUARE_1:69
          .=1/(sqrt(1+(q`1/(1))^2))^2+(q`1)^2/(sqrt(1+(q`1/(1))^2))^2
                        by SQUARE_1:59,69
          .=1/(1+(q`1)^2)+(q`1)^2/(sqrt(1+(q`1)^2))^2 by A19,SQUARE_1:def 4
          .=1/(1+(q`1)^2)+(q`1)^2/(1+(q`1)^2) by A19,SQUARE_1:def 4
          .=(1+(q`1)^2)/(1+(q`1)^2) by XCMPLX_1:63
          .=1 by A19,XCMPLX_1:60;
            0<=|.(|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|).|
                               by TOPRNS_1:26;
          then |.(|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|).|=1
                               by A21,SQUARE_1:83,89;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A2,A3,A17;
        case -1=q`1 & -1<=q`2 & q`2<=1;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A16;
        case 1=q`1 & -1<=q`2 & q`2<=1;
         hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1
                                     by A16;
        end;
       hence ex p2 being Point of TOP-REAL 2 st p2=y & |.p2.|=1;
      end;
     hence y in Cb by A1;
    end;
   let y be set;assume y in Cb;
     then consider p2 being Point of TOP-REAL 2 such that
     A22: p2=y & |.p2.|=1 by A1;
     set q=p2;
       now per cases;
     case q=0.REAL 2;
       hence contradiction by A22,TOPRNS_1:24;
     case A23:q<>0.REAL 2 &
          (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          set px=|[q`1*sqrt(1+(q`2/q`1)^2),q`2*sqrt(1+(q`2/q`1)^2)]|;
        A24: px`1 = q`1*sqrt(1+(q`2/q`1)^2) &
         px`2 = q`2*sqrt(1+(q`2/q`1)^2) by EUCLID:56;
          1+(q`2/q`1)^2>0 by Lm1;
        then A25:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
        A26: 1+(px`2/px`1)^2>0 by Lm1;
        A27:px`2/px`1=q`2/q`1 by A24,A25,XCMPLX_1:92;
        A28: q`1=q`1*sqrt(1+(q`2/q`1)^2)/(sqrt(1+(q`2/q`1)^2))by A25,XCMPLX_1:
90
          .=px`1/(sqrt(1+(q`2/q`1)^2)) by EUCLID:56;
        A29: q`2=q`2*sqrt(1+(q`2/q`1)^2)/(sqrt(1+(q`2/q`1)^2))by A25,XCMPLX_1:
90
          .=px`2/(sqrt(1+(q`2/q`1)^2)) by EUCLID:56;
        A30: |.q.|^2=q`1^2+q`2^2 by JGRAPH_1:46;
        A31:now assume px`1=0 & px`2=0;
          then A32:q`1*sqrt(1+(q`2/q`1)^2)=0 & q`2*sqrt(1+(q`2/q`1)^2)=0
                                    by EUCLID:56;
          then A33:q`1=0 by A25,XCMPLX_1:6;
            q`2=0 by A25,A32,XCMPLX_1:6;
         hence contradiction by A23,A33,EUCLID:57,58;
        end;
          q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 &
        q`2*sqrt(1+(q`2/q`1)^2) <= (-q`1)*sqrt(1+(q`2/q`1)^2)
                             by A23,A25,AXIOMS:25;
        then A34: q`2<=q`1 & (-q`1)*sqrt(1+(q`2/q`1)^2) <= q`2*sqrt(1+(q`2/q`1)
^2)
           or px`2>=px`1 & px`2<=-px`1 by A24,A25,AXIOMS:25,XCMPLX_1:175;
        then A35:px`2<=px`1 & -px`1<=px`2 or px`2>=px`1 & px`2<=-px`1
                                by A24,A25,AXIOMS:25,XCMPLX_1:175;
    then A36:Sq_Circ.px=|[px`1/sqrt(1+(px`2/px`1)^2),px`2/sqrt(1+(px`2/px`1)^2)
]|
                                 by A31,Def1,JGRAPH_2:11;
        A37:px`1/sqrt(1+(px`2/px`1)^2)=q`1 by A24,A25,A27,XCMPLX_1:90;
         px`2/sqrt(1+(px`2/px`1)^2)=q`2 by A24,A25,A27,XCMPLX_1:90;
        then A38:q=Sq_Circ.px by A36,A37,EUCLID:57;
        A39: dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
         not px`1=0 by A31,A35;
        then A40: (px`1)^2<>0 by SQUARE_1:73;
           (px`1)^2/(sqrt(1+(px`2/px`1)^2))^2+(px`2/sqrt(1+(px`2/px`1)^2))^2=1
                            by A22,A27,A28,A29,A30,SQUARE_1:59,69;
      then (px`1)^2/(sqrt(1+(px`2/px`1)^2))^2+(px`2)^2/(sqrt(1+(px`2/px`1)^2))
^2=1
                            by SQUARE_1:69;
         then (px`1)^2/(1+(px`2/px`1)^2)+(px`2)^2/(sqrt(1+(px`2/px`1)^2))^2=1
                            by A26,SQUARE_1:def 4;
         then (px`1)^2/(1+(px`2/px`1)^2)+(px`2)^2/(1+(px`2/px`1)^2)=1
                            by A26,SQUARE_1:def 4;
         then (px`1)^2/(1+(px`2/px`1)^2)*(1+(px`2/px`1)^2)
           +(px`2)^2/(1+(px`2/px`1)^2)*(1+(px`2/px`1)^2)=1 *(1+(px`2/px`1)^2)
                            by XCMPLX_1:8;
    then (px`1)^2+(px`2)^2/(1+(px`2/px`1)^2)*(1+(px`2/px`1)^2)=1 *(1+(px`2/px
`1)^2)
                            by A26,XCMPLX_1:88;
         then (px`1)^2+(px`2)^2=1 *(1+(px`2/px`1)^2) by A26,XCMPLX_1:88
         .=1+(px`2)^2/(px`1)^2 by SQUARE_1:69;
         then (px`1)^2+(px`2)^2-1=(px`2)^2/(px`1)^2 by XCMPLX_1:26;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2=(px`2)^2 by A40,XCMPLX_1:88;
         then ((px`1)^2+((px`2)^2-1))*(px`1)^2=(px`2)^2 by XCMPLX_1:29;
         then (px`1)^2*(px`1)^2+((px`2)^2-1)*(px`1)^2=(px`2)^2 by XCMPLX_1:8;
         then (px`1)^2*(px`1)^2+(px`1)^2*((px`2)^2-1)-(px`2)^2=0 by XCMPLX_1:14
;
         then 0=(px`1)^2*(px`1)^2+((px`1)^2*(px`2)^2-(px`1)^2*1)-(px`2)^2
                                   by XCMPLX_1:40
         .= (px`1)^2*(px`1)^2+(px`1)^2*(px`2)^2-(px`1)^2*1-(px`2)^2
                                   by XCMPLX_1:29
         .= (px`1)^2*(px`1)^2-(px`1)^2*1+(px`1)^2*(px`2)^2-1 *(px`2)^2
                                   by XCMPLX_1:29
         .= (px`1)^2*((px`1)^2-1)+(px`1)^2*(px`2)^2-1 *(px`2)^2 by XCMPLX_1:40
         .= (px`1)^2*((px`1)^2-1)+((px`1)^2*(px`2)^2-1 *(px`2)^2) by XCMPLX_1:
29
         .= (px`1)^2*((px`1)^2-1)+((px`1)^2-1)*(px`2)^2 by XCMPLX_1:40
         .= ((px`1)^2-1)*((px`1)^2+(px`2)^2) by XCMPLX_1:8;
         then (px`1)^2-1=0 or (px`1)^2+(px`2)^2=0 by XCMPLX_1:6;
         then (px`1)^2-1+1=1 or (px`1)^2+(px`2)^2=0;
         then A41: (px`1)^2=1 or px`1=0 & px`2=0 by COMPLEX1:2,XCMPLX_1:27;
            now per cases by A31,A41,Th2;
          case px`1=1;
           hence -1=px`1 & -1<=px`2 & px`2<=1 or px`1=1 & -1<=px`2 & px`2<=1
           or -1=px`2 & -1<=px`1 & px`1<=1 or 1=px`2 & -1<=px`1 & px`1<=1
                          by A24,A25,A34,AXIOMS:22,25,XCMPLX_1:175;
          case px`1=-1;
           hence -1=px`1 & -1<=px`2 & px`2<=1 or px`1=1 & -1<=px`2 & px`2<=1
           or -1=px`2 & -1<=px`1 & px`1<=1 or 1=px`2 & -1<=px`1 & px`1<=1
                          by A35,AXIOMS:22;
          end;
        then px in Kb by A1;
      hence ex x being set st x in dom Sq_Circ & x in Kb & y=Sq_Circ.x
                               by A22,A38,A39;
     case A42:q<>0.REAL 2 & not(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          set px=|[q`1*sqrt(1+(q`1/q`2)^2),q`2*sqrt(1+(q`1/q`2)^2)]|;
        A43:q<>0.REAL 2 & (q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 & q`1<=-q`2)
                          by A42,JGRAPH_2:23;
        A44: px`2 = q`2*sqrt(1+(q`1/q`2)^2) &
         px`1 = q`1*sqrt(1+(q`1/q`2)^2) by EUCLID:56;
          1+(q`1/q`2)^2>0 by Lm1;
        then A45:sqrt(1+(q`1/q`2)^2)>0 by SQUARE_1:93;
        A46: 1+(px`1/px`2)^2>0 by Lm1;
        A47:px`1/px`2=q`1/q`2 by A44,A45,XCMPLX_1:92;
        A48: q`2=px`2/(sqrt(1+(q`1/q`2)^2)) by A44,A45,XCMPLX_1:90;
        A49: q`1=px`1/(sqrt(1+(q`1/q`2)^2)) by A44,A45,XCMPLX_1:90;
        A50: |.q.|^2=q`2^2+q`1^2 by JGRAPH_1:46;
        A51:now assume A52: px`2=0 & px`1=0;
          then q`2=0 by A44,A45,XCMPLX_1:6;
         hence contradiction by A42,A44,A45,A52,XCMPLX_1:6;
        end;
          q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 &
        q`1*sqrt(1+(q`1/q`2)^2) <= (-q`2)*sqrt(1+(q`1/q`2)^2)
                             by A43,A45,AXIOMS:25;
        then A53: q`1<=q`2 & (-q`2)*sqrt(1+(q`1/q`2)^2) <= q`1*sqrt(1+(q`1/q`2)
^2)
           or px`1>=px`2 & px`1<=-px`2 by A44,A45,AXIOMS:25,XCMPLX_1:175;
        then A54:px`1<=px`2 & -px`2<=px`1 or px`1>=px`2 & px`1<=-px`2
                                by A44,A45,AXIOMS:25,XCMPLX_1:175;
     then A55:Sq_Circ.px=|[px`1/sqrt(1+(px`1/px`2)^2),px`2/sqrt(1+(px`1/px`2)^2
)]|
                                 by A51,Th14,JGRAPH_2:11;
        A56:px`2/sqrt(1+(px`1/px`2)^2)=q`2 by A44,A45,A47,XCMPLX_1:90;
         px`1/sqrt(1+(px`1/px`2)^2)=q`1 by A44,A45,A47,XCMPLX_1:90;
        then A57:q=Sq_Circ.px by A55,A56,EUCLID:57;
        A58: dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
         px`2<>0 by A51,A54;
        then A59: (px`2)^2<>0 by SQUARE_1:73;
           (px`2)^2/(sqrt(1+(px`1/px`2)^2))^2+(px`1/sqrt(1+(px`1/px`2)^2))^2=1
                            by A22,A47,A48,A49,A50,SQUARE_1:59,69;
      then (px`2)^2/(sqrt(1+(px`1/px`2)^2))^2+(px`1)^2/(sqrt(1+(px`1/px`2)^2))
^2=1
                            by SQUARE_1:69;
         then (px`2)^2/(1+(px`1/px`2)^2)+(px`1)^2/(sqrt(1+(px`1/px`2)^2))^2=1
                            by A46,SQUARE_1:def 4;
         then (px`2)^2/(1+(px`1/px`2)^2)+(px`1)^2/(1+(px`1/px`2)^2)=1
                            by A46,SQUARE_1:def 4;
         then (px`2)^2/(1+(px`1/px`2)^2)*(1+(px`1/px`2)^2)
           +(px`1)^2/(1+(px`1/px`2)^2)*(1+(px`1/px`2)^2)=1 *(1+(px`1/px`2)^2)
                            by XCMPLX_1:8;
    then (px`2)^2+(px`1)^2/(1+(px`1/px`2)^2)*(1+(px`1/px`2)^2)=1 *(1+(px`1/px
`2)^2)
                            by A46,XCMPLX_1:88;
         then (px`2)^2+(px`1)^2=1 *(1+(px`1/px`2)^2) by A46,XCMPLX_1:88;
         then (px`2)^2+(px`1)^2=1+(px`1)^2/(px`2)^2 by SQUARE_1:69;
         then (px`2)^2+(px`1)^2-1=(px`1)^2/(px`2)^2 by XCMPLX_1:26;
         then ((px`2)^2+(px`1)^2-1)*(px`2)^2=(px`1)^2 by A59,XCMPLX_1:88;
         then ((px`2)^2+((px`1)^2-1))*(px`2)^2=(px`1)^2 by XCMPLX_1:29;
         then (px`2)^2*(px`2)^2+((px`1)^2-1)*(px`2)^2=(px`1)^2 by XCMPLX_1:8;
         then (px`2)^2*(px`2)^2+(px`2)^2*((px`1)^2-1)-(px`1)^2=0 by XCMPLX_1:14
;
         then 0=(px`2)^2*(px`2)^2+((px`2)^2*(px`1)^2-(px`2)^2*1)-(px`1)^2
                                   by XCMPLX_1:40
         .=(px`2)^2*(px`2)^2+(px`2)^2*(px`1)^2-(px`2)^2*1-(px`1)^2
                                   by XCMPLX_1:29
         .=(px`2)^2*(px`2)^2-(px`2)^2*1+(px`2)^2*(px`1)^2-1 *(px`1)^2
                                   by XCMPLX_1:29
         .=(px`2)^2*((px`2)^2-1)+(px`2)^2*(px`1)^2-1 *(px`1)^2 by XCMPLX_1:40
         .=(px`2)^2*((px`2)^2-1)+((px`2)^2*(px`1)^2-1 *(px`1)^2) by XCMPLX_1:29
         .=(px`2)^2*((px`2)^2-1)+((px`2)^2-1)*(px`1)^2 by XCMPLX_1:40
         .=((px`2)^2-1)*((px`2)^2+(px`1)^2) by XCMPLX_1:8;
         then (px`2)^2-1=0 or (px`2)^2+(px`1)^2=0 by XCMPLX_1:6;
         then (px`2)^2-1+1=1 or (px`2)^2+(px`1)^2 =0;
         then A60: (px`2)^2=1 or px`2=0 & px`1=0 by COMPLEX1:2,XCMPLX_1:27;
            now per cases by A51,A60,Th2;
          case px`2=1;
           hence -1=px`2 & -1<=px`1 & px`1<=1 or px`2=1 & -1<=px`1 & px`1<=1
           or -1=px`1 & -1<=px`2 & px`2<=1 or 1=px`1 & -1<=px`2 & px`2<=1
                          by A44,A45,A53,AXIOMS:22,25,XCMPLX_1:175;
          case px`2=-1;
           hence -1=px`2 & -1<=px`1 & px`1<=1 or px`2=1 & -1<=px`1 & px`1<=1
           or -1=px`1 & -1<=px`2 & px`2<=1 or 1=px`1 & -1<=px`2 & px`2<=1
                          by A54,AXIOMS:22;
          end;
        then px in Kb by A1;
      hence ex x being set st x in dom Sq_Circ & x in Kb & y=Sq_Circ.x
                               by A22,A57,A58;
     end;
    hence thesis by FUNCT_1:def 12;
 end;

theorem Th34: for P,Kb being Subset of TOP-REAL 2,f being map of
 (TOP-REAL 2)|Kb,(TOP-REAL 2)|P st
 Kb={q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1}
 & f is_homeomorphism
 holds P is_simple_closed_curve
 proof let P,Kb be Subset of TOP-REAL 2,f be map of
  (TOP-REAL 2)|Kb,(TOP-REAL 2)|P;
  assume A1: Kb={q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1}
     & f is_homeomorphism;
   set v= |[1,0]|;
     v`1=1 & v`2=0 by EUCLID:56;
    then A2: |[1,0]| in
    {q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1};
    dom f=[#]((TOP-REAL 2)|Kb) by A1,TOPS_2:def 5
  .=Kb by PRE_TOPC:def 10;
  then f.(|[1,0]|) in rng f by A1,A2,FUNCT_1:12;
  then reconsider PP=P as non empty Subset of TOP-REAL 2 by JORDAN1:1;
  reconsider Kbb=Kb as non empty Subset of TOP-REAL 2 by A1,A2;
  reconsider Kbd=Kbb as non empty Subset of TOP-REAL 2;
  reconsider g=f as map of (TOP-REAL 2)|Kbb,(TOP-REAL 2)|PP;
  set b=1,a=0,d=1,c =0;
  set A=2/(b-a),B=1-2*b/(b-a),C=2/(d-c),D=1-2*d/(d-c);
   defpred P[set,set] means
  (for t being Point of TOP-REAL 2 st t=$1 holds
    $2=|[A*(t`1)+B,C*(t`2)+D]|);
  A3:for x,y1,y2 being set st x in the carrier of TOP-REAL 2 &
     P[x,y1] & P[x,y2] holds y1 = y2
     proof let x,y1,y2 be set;
       assume A4:x in the carrier of TOP-REAL 2 & P[x,y1] & P[x,y2];
         then reconsider t=x as Point of TOP-REAL 2;
           y1=|[A*(t`1)+B,C*(t`2)+D]| by A4;
      hence y1 = y2 by A4;
     end;
   A5:for x being set st x in the carrier of TOP-REAL 2
        ex y being set st P[x,y]
      proof let x be set;assume x in the carrier of TOP-REAL 2;
         then reconsider t2=x as Point of TOP-REAL 2;
         reconsider y2=|[A*(t2`1)+B,C*(t2`2)+D]| as set;
           (for t being Point of TOP-REAL 2 st t=x holds
          y2 =|[A*(t`1)+B,C*(t`2)+D]|);
        hence ex y being set st P[x,y];
      end;
     ex ff being Function st dom ff=the carrier of TOP-REAL 2 &
   for x being set st x in the carrier of TOP-REAL 2 holds
   P[x,ff.x] from FuncEx(A3,A5);
   then consider ff being Function such that
   A6: dom ff=the carrier of TOP-REAL 2 &
   for x being set st x in the carrier of TOP-REAL 2 holds
   (for t being Point of TOP-REAL 2 st t=x holds
    ff.x=|[A*(t`1)+B,C*(t`2)+D]|);
   A7:(for t being Point of TOP-REAL 2 holds
    ff.t=|[A*(t`1)+B,C*(t`2)+D]|) by A6;
     for x being set st x in the carrier of TOP-REAL 2 holds
                                  ff.x in the carrier of TOP-REAL 2
      proof let x be set;assume
         x in the carrier of TOP-REAL 2;
       then reconsider t=x as Point of TOP-REAL 2;
         ff.t=|[A*(t`1)+B,C*(t`2)+D]| by A6;
       hence ff.x in the carrier of TOP-REAL 2;
      end;
   then ff is Function of the carrier of TOP-REAL 2,the carrier of TOP-REAL 2
                   by A6,FUNCT_2:5;
   then reconsider ff as map of TOP-REAL 2,TOP-REAL 2 ;
   A8:ff is continuous by A7,JGRAPH_2:53;
   reconsider f11=ff|(R^2-unit_square)
         as map of (TOP-REAL 2)|R^2-unit_square,(TOP-REAL 2) by Th12;
   A9:dom f11=(dom ff)/\ (R^2-unit_square) by FUNCT_1:68
   .= R^2-unit_square by A6,XBOOLE_1:28;
   A10: f11 is continuous by A8,TOPMETR:10;
     ff is one-to-one
   proof let x1,x2 be set;assume A11: x1 in dom ff & x2 in dom ff
      & ff.x1=ff.x2;
     then reconsider p1=x1,p2=x2 as Point of TOP-REAL 2;
     A12: ff.x1= |[A*(p1`1)+B,C*(p1`2)+D]| by A6;
       ff.x2= |[A*(p2`1)+B,C*(p2`2)+D]| by A6;
     then A*(p1`1)+B=A*(p2`1)+B & C*(p1`2)+D=C*(p2`2)+D
                           by A11,A12,SPPOL_2:1;
     then A*(p1`1)=A*(p2`1)+B-B & C*(p1`2)+D-D=C*(p2`2)+D-D by XCMPLX_1:26;
     then A*(p1`1)=A*(p2`1) & C*(p1`2)=C*(p2`2)+D-D by XCMPLX_1:26;
     then (p1`1)=A*(p2`1)/A & C*(p1`2)/C=C*(p2`2)/C by XCMPLX_1:26,90;
     then (p1`1)=(p2`1) & (p1`2)=C*(p2`2)/C by XCMPLX_1:90;
     then (p1`1)=(p2`1) & (p1`2)=(p2`2) by XCMPLX_1:90;
    hence x1=x2 by TOPREAL3:11;
   end;
   then A13:f11 is one-to-one by FUNCT_1:84;
   set X=(TOP-REAL 2)|R^2-unit_square;
   A14:Kbd c= rng f11
    proof let y be set;assume A15:y in Kbd;
      then reconsider py=y as Point of TOP-REAL 2;
      set t=|[(py`1-B)/2,(py`2-D)/2]|;
      A16:t`1=(py`1-B)/2 & t`2=(py`2-D)/2 by EUCLID:56;
      then 2*t`1=py`1-B by XCMPLX_1:88;
      then A17:py`1=A*(t`1)+B by XCMPLX_1:27;
      consider q such that
      A18: py=q &(-1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or
      1=q`2 & -1<=q`1 & q`1<=1) by A1,A15;
        now per cases by A18;
      case A19: -1=py`1 & -1<=py`2 & py`2<=1;
        then 0-1<=py`2;
        then 0<= py`2+1 by REAL_1:86;
        then 0<= (py`2--1) by XCMPLX_1:151;
then A20:     0/2 <= (py`2-D)/2 by REAL_1:73;
          2-1>=py`2 by A19;
        then 2>= py`2+1 by REAL_1:84;
        then 2>= (py`2--1) by XCMPLX_1:151;
        then 2/2 >= (py`2-D)/2 by REAL_1:73;
       hence t`1 = 0 & t`2 <= 1 & t`2 >= 0 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 1 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 0 or
        t`1 = 1 & t`2 <= 1 & t`2 >= 0 by A19,A20,EUCLID:56;
      case A21: py`1=1 & -1<=py`2 & py`2<=1;
        then 0-1<=py`2;
        then 0<= py`2+1 by REAL_1:86;
        then 0<= (py`2--1) by XCMPLX_1:151;
then A22:     0/2 <= (py`2-D)/2 by REAL_1:73;
          2-1>=py`2 by A21;
        then 2>= py`2+1 by REAL_1:84;
        then 2>= (py`2--1) by XCMPLX_1:151;
        then 2/2 >= (py`2-D)/2 by REAL_1:73;
       hence t`1 = 0 & t`2 <= 1 & t`2 >= 0 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 1 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 0 or
        t`1 = 1 & t`2 <= 1 & t`2 >= 0 by A21,A22,EUCLID:56;
      case A23: -1=py`2 & -1<=py`1 & py`1<=1;
        then 0-1<=py`1;
        then 0<= py`1+1 by REAL_1:86;
        then 0<= (py`1--1) by XCMPLX_1:151;
then A24:     0/2 <= (py`1-B)/2 by REAL_1:73;
          2-1>=py`1 by A23;
        then 2>= py`1+1 by REAL_1:84;
        then 2>= (py`1--1) by XCMPLX_1:151;
        then 2/2 >= (py`1-B)/2 by REAL_1:73;
       hence t`1 = 0 & t`2 <= 1 & t`2 >= 0 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 1 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 0 or
        t`1 = 1 & t`2 <= 1 & t`2 >= 0 by A23,A24,EUCLID:56;
      case A25: 1=py`2 & -1<=py`1 & py`1<=1;
        then 0-1<=py`1;
        then 0<= py`1+1 by REAL_1:86;
        then 0<= (py`1--1) by XCMPLX_1:151;
then A26:     0/2 <= (py`1-B)/2 by REAL_1:73;
          2-1>=py`1 by A25;
        then 2>= py`1+1 by REAL_1:84;
        then 2>= (py`1--1) by XCMPLX_1:151;
        then 2/2 >= (py`1-B)/2 by REAL_1:73;
       hence t`1 = 0 & t`2 <= 1 & t`2 >= 0 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 1 or
        t`1 <= 1 & t`1 >= 0 & t`2 = 0 or
        t`1 = 1 & t`2 <= 1 & t`2 >= 0 by A25,A26,EUCLID:56;
      end;
      then A27:t in (R^2-unit_square) by TOPREAL1:def 3;
        t`2*2=py`2-D by A16,XCMPLX_1:88;
      then 2*t`2+D=py`2 by XCMPLX_1:27;
      then py=|[A*(t`1)+B,C*(t`2)+D]| by A17,EUCLID:57;
      then py=ff.t by A6 .=f11.t by A27,FUNCT_1:72;
     hence y in rng f11 by A9,A27,FUNCT_1:def 5;
    end;
     rng f11 c= Kbd
    proof let y be set;assume y in rng f11;
      then consider x being set such that
      A28: x in dom f11 & y=f11.x by FUNCT_1:def 5;
      reconsider t=x as Point of TOP-REAL 2 by A9,A28;
      consider p such that
      A29: t=p &( p`1 = 0 & p`2 <= 1 & p`2 >= 0 or
        p`1 <= 1 & p`1 >= 0 & p`2 = 1 or
        p`1 <= 1 & p`1 >= 0 & p`2 = 0 or
        p`1 = 1 & p`2 <= 1 & p`2 >= 0) by A9,A28,TOPREAL1:def 3;
      A30:y=ff.t by A9,A28,FUNCT_1:72
      .= |[A*(t`1)+B,C*(t`2)+D]| by A6;
      then reconsider qy=y as Point of TOP-REAL 2;
        now per cases by A29;
      suppose A31: t`1 = 0 & t`2 <= 1 & t`2 >= 0;
          qy`2=2*(t`2)+(-1) by A30,EUCLID:56 .=2*(t`2)-1 by XCMPLX_0:def 8;
        then A32:qy`2+1=2*(t`2) by XCMPLX_1:27;
          2*0<=2*t`2 by A31,AXIOMS:25;
        then A33: 0-1<=qy`2+1-1 by A32,REAL_1:49;
          2*1>=2*t`2 by A31,AXIOMS:25;
        then 1+1-1>=qy`2+1-1 by A32,REAL_1:49;
       hence -1=qy`1 & -1<=qy`2 & qy`2<=1 or
        qy`1=1 & -1<=qy`2 & qy`2<=1 or
        -1=qy`2 & -1<=qy`1 & qy`1<=1 or
        1=qy`2 & -1<=qy`1 & qy`1<=1 by A30,A31,A33,EUCLID:56,XCMPLX_1:26;
      suppose A34: t`1 <= 1 & t`1 >= 0 & t`2 = 1;
          qy`1=2*(t`1)+(-1) by A30,EUCLID:56 .=2*(t`1)-1 by XCMPLX_0:def 8;
        then A35:qy`1+1=2*(t`1) by XCMPLX_1:27;
          2*0<=2*t`1 by A34,AXIOMS:25;
        then A36: 0-1<=qy`1+1-1 by A35,REAL_1:49;
          2*1>=2*t`1 by A34,AXIOMS:25;
        then 1+1-1>=qy`1+1-1 by A35,REAL_1:49;
       hence -1=qy`1 & -1<=qy`2 & qy`2<=1 or
        qy`1=1 & -1<=qy`2 & qy`2<=1 or
        -1=qy`2 & -1<=qy`1 & qy`1<=1 or
        1=qy`2 & -1<=qy`1 & qy`1<=1 by A30,A34,A36,EUCLID:56,XCMPLX_1:26;
      suppose A37: t`1 <= 1 & t`1 >= 0 & t`2 = 0;
          qy`1=2*(t`1)+(-1) by A30,EUCLID:56 .=2*(t`1)-1 by XCMPLX_0:def 8;
        then A38:qy`1+1=2*(t`1) by XCMPLX_1:27;
          2*0<=2*t`1 by A37,AXIOMS:25;
        then A39: 0-1<=qy`1+1-1 by A38,REAL_1:49;
          2*1>=2*t`1 by A37,AXIOMS:25;
        then 1+1-1>=qy`1+1-1 by A38,REAL_1:49;
       hence -1=qy`1 & -1<=qy`2 & qy`2<=1 or
        qy`1=1 & -1<=qy`2 & qy`2<=1 or
        -1=qy`2 & -1<=qy`1 & qy`1<=1 or
        1=qy`2 & -1<=qy`1 & qy`1<=1 by A30,A37,A39,EUCLID:56,XCMPLX_1:26;
      suppose A40: t`1 = 1 & t`2 <= 1 & t`2 >= 0;
          qy`2=2*(t`2)+(-1) by A30,EUCLID:56 .=2*(t`2)-1 by XCMPLX_0:def 8;
        then A41:qy`2+1=2*(t`2) by XCMPLX_1:27;
          2*0<=2*t`2 by A40,AXIOMS:25;
        then A42: 0-1<=qy`2+1-1 by A41,REAL_1:49;
          2*1>=2*t`2 by A40,AXIOMS:25;
        then 1+1-1>=qy`2+1-1 by A41,REAL_1:49;
       hence -1=qy`1 & -1<=qy`2 & qy`2<=1 or
        qy`1=1 & -1<=qy`2 & qy`2<=1 or
        -1=qy`2 & -1<=qy`1 & qy`1<=1 or
        1=qy`2 & -1<=qy`1 & qy`1<=1 by A30,A40,A42,EUCLID:56,XCMPLX_1:26;
      end;
     hence y in Kbd by A1;
    end;
   then Kbd=rng f11 by A14,XBOOLE_0:def 10;
   then consider f1 being map of X,((TOP-REAL 2)|Kbd) such that
   A43: f11=f1 & f1 is_homeomorphism by A10,A13,JGRAPH_1:64;
   reconsider f22=f1 as map of X,((TOP-REAL 2)|Kbb);
   reconsider g as map of (TOP-REAL 2)|Kbb,(TOP-REAL 2)|PP;
   reconsider h=g*f22 as map of (TOP-REAL 2)|R^2-unit_square,(TOP-REAL 2)|PP;
     h is_homeomorphism by A1,A43,TOPS_2:71;
  hence thesis by TOPREAL2:def 1;
 end;

theorem Th35: for Kb being Subset of TOP-REAL 2
 st Kb={q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1}
 holds Kb is_simple_closed_curve & Kb is compact
 proof let Kb be Subset of TOP-REAL 2;
   assume A1:Kb={q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1};
   set v= |[1,0]|;
     v`1=1 & v`2=0 by EUCLID:56;
    then |[1,0]| in {q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1};
   then reconsider Kbd=Kb as non empty Subset of TOP-REAL 2 by A1;
     id ((TOP-REAL 2)|Kbd) is_homeomorphism by TOPGRP_1:20;
   hence A2:Kb is_simple_closed_curve by A1,Th34;
    set P=Kb;
    consider f being map of (TOP-REAL 2)|R^2-unit_square, (TOP-REAL 2)|P
     such that
A3: f is_homeomorphism by A2,TOPREAL2:def 1;
    per cases;
    suppose A4: P is empty;
        Kbd <>{};
     hence thesis by A4;
    suppose P is non empty;
      then reconsider R = P as non empty Subset of TOP-REAL 2;
        f is continuous & rng f = [#]((TOP-REAL 2)|P) by A3,TOPS_2:def 5;
      then (TOP-REAL 2)|R is compact by COMPTS_1:23;
     hence thesis by COMPTS_1:12;
 end;

theorem for Cb being Subset of TOP-REAL 2 st
  Cb={p where p is Point of TOP-REAL 2: |.p.|=1}
 holds Cb is_simple_closed_curve
 proof let Cb be Subset of TOP-REAL 2;
  assume A1: Cb={p where p is Point of TOP-REAL 2: |.p.|=1};
   A2:(|[1,0]|)`1=1 & (|[1,0]|)`2=0 by EUCLID:56;
     |.(|[1,0]|).|=sqrt(((|[1,0]|)`1)^2+((|[1,0]|)`2)^2) by JGRAPH_1:47
     .=1 by A2,SQUARE_1:59,60,83;
    then |[1,0]| in Cb by A1;
   then reconsider Cbb=Cb as non empty Subset of TOP-REAL 2;
   set v= |[1,0]|;
     v`1=1 & v`2=0 by EUCLID:56;
then A3:  |[1,0]| in {q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1};
      defpred P[Point of TOP-REAL 2] means
    -1=$1`1 & -1<=$1`2 & $1`2<=1 or $1`1=1 & -1<=$1`2 & $1`2<=1
      or -1=$1`2 & -1<=$1`1 & $1`1<=1 or 1=$1`2 & -1<=$1`1 & $1`1<=1;
     {q where q is Element of TOP-REAL 2: P[q]}
       is Subset of TOP-REAL 2 from SubsetD;
   then reconsider Kb= {q: -1=q`1 & -1<=q`2 & q`2<=1 or q`1=1 & -1<=q`2 & q`2<=
1
      or -1=q`2 & -1<=q`1 & q`1<=1 or 1=q`2 & -1<=q`1 & q`1<=1}
      as non empty Subset of TOP-REAL 2 by A3;
    A4:the carrier of (TOP-REAL 2)|Kb=Kb by JORDAN1:1;
   A5:dom Sq_Circ = the carrier of TOP-REAL 2 by FUNCT_2:def 1;
   A6:dom (Sq_Circ|Kb)=(dom Sq_Circ)/\ Kb by FUNCT_1:68
   .=the carrier of ((TOP-REAL 2)|Kb) by A4,A5,XBOOLE_1:28;
   A7:rng (Sq_Circ|Kb) c= rng (Sq_Circ) by FUNCT_1:76;
   A8:rng (Sq_Circ|Kb) c= (Sq_Circ|Kb).:(the carrier of ((TOP-REAL 2)|Kb))
    proof let u be set;assume u in rng (Sq_Circ|Kb);
      then consider z being set such that
      A9: z in dom ((Sq_Circ|Kb)) & u=(Sq_Circ|Kb).z by FUNCT_1:def 5;
     thus u in (Sq_Circ|Kb).:(the carrier of ((TOP-REAL 2)|Kb))
                       by A6,A9,FUNCT_1:def 12;
    end;
     (Sq_Circ|Kb).: (the carrier of ((TOP-REAL 2)|Kb))
        = Sq_Circ.:Kb by A4,RFUNCT_2:5
        .= Cb by A1,Th33
        .=the carrier of (TOP-REAL 2)|Cbb by JORDAN1:1;
   then Sq_Circ|Kb is Function of the carrier of (TOP-REAL 2)|Kb,
      the carrier of (TOP-REAL 2)|Cbb by A6,A8,FUNCT_2:4;
   then reconsider f0=Sq_Circ|Kb
         as map of (TOP-REAL 2)|Kb, (TOP-REAL 2)|Cbb ;
     rng (Sq_Circ|Kb) c= the carrier of (TOP-REAL 2) by A7,XBOOLE_1:1;
   then f0 is Function of the carrier of (TOP-REAL 2)|Kb,
     the carrier of TOP-REAL 2 by A6,FUNCT_2:4;
   then reconsider f00=f0 as map of (TOP-REAL 2)|Kb,TOP-REAL 2;
   A10:rng f0 = (Sq_Circ|Kb).:
          (the carrier of ((TOP-REAL 2)|Kb)) by FUNCT_2:45
        .= Sq_Circ.:Kb by A4,RFUNCT_2:5
        .= Cb by A1,Th33;
   A11:f0 is one-to-one by FUNCT_1:84;
   consider h being map of (TOP-REAL 2),(TOP-REAL 2)
     such that A12: h=Sq_Circ & h is continuous by Th31;
   A13:f00 is continuous by A12,TOPMETR:10;
     Kb is compact by Th35;
   then (TOP-REAL 2)|Kb is compact by COMPTS_1:12;
   then ex f1 being map of (TOP-REAL 2)|Kb,(TOP-REAL 2)|Cbb st
   f00=f1 & f1 is_homeomorphism by A10,A11,A13,JGRAPH_1:64;
  hence thesis by Th34;
 end;

begin :: The Fashoda Meet Theorem for the Circle

theorem for K0,C0 being Subset of TOP-REAL 2 st
 K0={p: -1<=p`1 & p`1<=1 & -1<=p`2 & p`2<=1}
& C0={p1 where p1 is Point of TOP-REAL 2: |.p1.|<=1}
holds Sq_Circ"(C0) c= K0
proof let K0,C0 be Subset of TOP-REAL 2;
 assume A1: K0={p: -1<=p`1 & p`1<=1 & -1<=p`2 & p`2<=1}
  & C0={p1 where p1 is Point of TOP-REAL 2: |.p1.|<=1};
  let x be set;assume A2: x in Sq_Circ"(C0);
    then A3:x in dom Sq_Circ & Sq_Circ.x in C0 by FUNCT_1:def 13;
    reconsider px=x as Point of TOP-REAL 2 by A2;
    set q=px;
      now per cases;
    case q=0.REAL 2;
      hence -1<=px`1 & px`1<=1 & -1<=px`2 & px`2<=1 by JGRAPH_2:11;
    case A4:q<>0.REAL 2 &
          (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
        then A5:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|
                                 by Def1;
        A6: (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`1
         = q`1/sqrt(1+(q`2/q`1)^2) &
         (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`2
         = q`2/sqrt(1+(q`2/q`1)^2) by EUCLID:56;
        A7:(px`1)^2 >=0 by SQUARE_1:72;
        A8:1+(q`2/q`1)^2>0 by Lm1;
        consider p1 being Point of TOP-REAL 2 such that
        A9: p1=Sq_Circ.q & |.p1.|<=1 by A1,A3;
           |.p1.| >=0 by TOPRNS_1:26;
         then (|.p1.|)^2<= |.p1.| by A9,Th3;
        then A10: (|.p1.|)^2<=1 by A9,AXIOMS:22;
         now assume A11:px`1=0;
          then px`2=0 by A4;
         hence contradiction by A4,A11,EUCLID:57,58;
        end;
        then A12: (px`1)^2<>0 by SQUARE_1:73;
          (|.p1.|)^2= (q`1/sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by A5,A6,A9,JGRAPH_1:46
               .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
          .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
               .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by A8,SQUARE_1:def 4
               .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(1+(q`2/q`1)^2)
                              by A8,SQUARE_1:def 4
               .= ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2) by XCMPLX_1:63;
        then ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2)*(1+(q`2/q`1)^2)<=1 *(1+(q`2/q`1
)^2)
                              by A8,A10,AXIOMS:25;
        then ((q`1)^2+(q`2)^2)<=(1+(q`2/q`1)^2) by A8,XCMPLX_1:88;
         then (px`1)^2+(px`2)^2<=1+(px`2)^2/(px`1)^2 by SQUARE_1:69;
         then (px`1)^2+(px`2)^2-1<=1+(px`2)^2/(px`1)^2-1 by REAL_1:49;
         then (px`1)^2+(px`2)^2-1<=(px`2)^2/(px`1)^2 by XCMPLX_1:26;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2<=(px`2)^2/(px`1)^2*(px`1)^2
                              by A7,AXIOMS:25;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2<=(px`2)^2 by A12,XCMPLX_1:88;
         then ((px`1)^2+((px`2)^2-1))*(px`1)^2<=(px`2)^2 by XCMPLX_1:29;
         then (px`1)^2*(px`1)^2+((px`2)^2-1)*(px`1)^2<=(px`2)^2 by XCMPLX_1:8;
         then (px`1)^2*(px`1)^2+(px`1)^2*((px`2)^2-1)-(px`2)^2<=0 by REAL_2:106
;
         then (px`1)^2*(px`1)^2+((px`1)^2*(px`2)^2-(px`1)^2*1)-(px`2)^2<=0
                                   by XCMPLX_1:40;
         then (px`1)^2*(px`1)^2+(px`1)^2*(px`2)^2-(px`1)^2*1-(px`2)^2<=0
                                   by XCMPLX_1:29;
         then (px`1)^2*(px`1)^2-(px`1)^2*1+(px`1)^2*(px`2)^2-1 *(px`2)^2<=0
                                   by XCMPLX_1:29;
         then (px`1)^2*((px`1)^2-1)+(px`1)^2*(px`2)^2-1 *(px`2)^2<=0
                                   by XCMPLX_1:40;
         then (px`1)^2*((px`1)^2-1)+((px`1)^2*(px`2)^2-1 *(px`2)^2)<=0
                                   by XCMPLX_1:29;
         then (px`1)^2*((px`1)^2-1)+((px`1)^2-1)*(px`2)^2<=0 by XCMPLX_1:40;
         then A13:((px`1)^2-1)*((px`1)^2+(px`2)^2)<=0 by XCMPLX_1:8;
         A14:now assume ((px`1)^2+(px`2)^2)=0;
          then px`1=0 & px`2=0 by COMPLEX1:2;
          hence contradiction by A4,EUCLID:57,58;
         end;
           (px`2)^2>=0 by SQUARE_1:72;
         then ((px`1)^2+(px`2)^2)>=0+0 by A7,REAL_1:55;
         then A15: (px`1)^2-1<=0 by A13,A14,REAL_2:129;
         then A16: -1<=px`1 & px`1<=1 by Th5;
         then (q`2<=1 & --q`1>=-q`2 or q`2>=-1 & -q`2>=--q`1)
                   by A4,AXIOMS:22,REAL_1:50;
         then (q`2<=1 & 1>=-q`2 or q`2>=-1 & -q`2>=q`1) by A16,AXIOMS:22;
         then (q`2<=1 & -1<=--q`2 or q`2>=-1 & -q`2>=-1)
                   by A16,AXIOMS:22,REAL_1:50;
      hence -1<=px`1 & px`1<=1 & -1<=px`2 & px`2<=1 by A15,Th5,REAL_1:50;
    case A17:q<>0.REAL 2 &
          not (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
        then A18:Sq_Circ.q=|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|
                                 by Def1;
        A19: (|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|)`2
         = q`2/sqrt(1+(q`1/q`2)^2) &
         (|[q`1/sqrt(1+(q`1/q`2)^2),q`2/sqrt(1+(q`1/q`2)^2)]|)`1
         = q`1/sqrt(1+(q`1/q`2)^2) by EUCLID:56;
        A20:q<>0.REAL 2 & (q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 & q`1<=-q`2)
                          by A17,JGRAPH_2:23;
        A21:(px`2)^2 >=0 by SQUARE_1:72;
        A22:1+(q`1/q`2)^2>0 by Lm1;
        consider p1 being Point of TOP-REAL 2 such that
        A23: p1=Sq_Circ.q & |.p1.|<=1 by A1,A3;
           |.p1.| >=0 by TOPRNS_1:26;
         then (|.p1.|)^2<= |.p1.| by A23,Th3;
        then A24: (|.p1.|)^2<=1 by A23,AXIOMS:22;
          px`2<>0 by A17,A20;
        then A25: (px`2)^2<>0 by SQUARE_1:73;
          (|.p1.|)^2= (q`1/sqrt(1+(q`1/q`2)^2))^2+(q`2/sqrt(1+(q`1/q`2)^2))^2
                              by A18,A19,A23,JGRAPH_1:46
               .= (q`2)^2/(sqrt(1+(q`1/q`2)^2))^2+(q`1/sqrt(1+(q`1/q`2)^2))^2
                              by SQUARE_1:69
           .= (q`2)^2/(sqrt(1+(q`1/q`2)^2))^2+(q`1)^2/(sqrt(1+(q`1/q`2)^2))^2
                              by SQUARE_1:69
               .= (q`2)^2/(1+(q`1/q`2)^2)+(q`1)^2/(sqrt(1+(q`1/q`2)^2))^2
                              by A22,SQUARE_1:def 4
               .= (q`2)^2/(1+(q`1/q`2)^2)+(q`1)^2/(1+(q`1/q`2)^2)
                              by A22,SQUARE_1:def 4
               .= ((q`2)^2+(q`1)^2)/(1+(q`1/q`2)^2) by XCMPLX_1:63;
        then ((q`2)^2+(q`1)^2)/(1+(q`1/q`2)^2)*(1+(q`1/q`2)^2)<=1 *(1+(q`1/q`2
)^2)
                              by A22,A24,AXIOMS:25;
        then ((q`2)^2+(q`1)^2)<=(1+(q`1/q`2)^2) by A22,XCMPLX_1:88;
         then (px`2)^2+(px`1)^2<=1+(px`1)^2/(px`2)^2 by SQUARE_1:69;
         then (px`2)^2+(px`1)^2-1<=1+(px`1)^2/(px`2)^2-1 by REAL_1:49;
         then (px`2)^2+(px`1)^2-1<=(px`1)^2/(px`2)^2 by XCMPLX_1:26;
         then ((px`2)^2+(px`1)^2-1)*(px`2)^2<=(px`1)^2/(px`2)^2*(px`2)^2
                              by A21,AXIOMS:25;
         then ((px`2)^2+(px`1)^2-1)*(px`2)^2<=(px`1)^2 by A25,XCMPLX_1:88;
         then ((px`2)^2+((px`1)^2-1))*(px`2)^2<=(px`1)^2 by XCMPLX_1:29;
         then (px`2)^2*(px`2)^2+((px`1)^2-1)*(px`2)^2<=(px`1)^2 by XCMPLX_1:8;
         then (px`2)^2*(px`2)^2+(px`2)^2*((px`1)^2-1)-(px`1)^2<=0 by REAL_2:106
;
         then (px`2)^2*(px`2)^2+((px`2)^2*(px`1)^2-(px`2)^2*1)-(px`1)^2<=0
                                   by XCMPLX_1:40;
         then (px`2)^2*(px`2)^2+(px`2)^2*(px`1)^2-(px`2)^2*1-(px`1)^2<=0
                                   by XCMPLX_1:29;
         then (px`2)^2*(px`2)^2-(px`2)^2*1+(px`2)^2*(px`1)^2-1 *(px`1)^2<=0
                                   by XCMPLX_1:29;
         then (px`2)^2*((px`2)^2-1)+(px`2)^2*(px`1)^2-1 *(px`1)^2<=0
                                   by XCMPLX_1:40;
         then (px`2)^2*((px`2)^2-1)+((px`2)^2*(px`1)^2-1 *(px`1)^2)<=0
                                   by XCMPLX_1:29;
         then (px`2)^2*((px`2)^2-1)+((px`2)^2-1)*(px`1)^2<=0 by XCMPLX_1:40;
         then A26:((px`2)^2-1)*((px`2)^2+(px`1)^2)<=0 by XCMPLX_1:8;
         A27:now assume ((px`2)^2+(px`1)^2)=0;
           then px`2=0 & px`1=0 by COMPLEX1:2;
          hence contradiction by A17;
         end;
           (px`1)^2>=0 by SQUARE_1:72;
         then ((px`2)^2+(px`1)^2)>=0+0 by A21,REAL_1:55;
         then A28: (px`2)^2-1<=0 by A26,A27,REAL_2:129;
         then -1<=px`2 & px`2<=1 by Th5;
         then (q`1<=1 & 1>=-q`1 or q`1>=-1 & -q`1>=-1) by A17,AXIOMS:22;
         then (q`1<=1 & -1<=--q`1 or q`1>=-1 & q`1<=1) by REAL_1:50;
      hence -1<=px`1 & px`1<=1 & -1<=px`2 & px`2<=1 by A28,Th5;
    end;
   hence x in K0 by A1;
end;

theorem Th38: for p holds
 (p=0.REAL 2 implies Sq_Circ".p=0.REAL 2) &
 ( (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2 implies
    Sq_Circ".p=|[p`1*sqrt(1+(p`2/p`1)^2),p`2*sqrt(1+(p`2/p`1)^2)]|)&
 (not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2 implies
    Sq_Circ".p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|)
  proof let p;
A1:  dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
    hereby assume A2:p=0.REAL 2; then Sq_Circ.p=p by Def1;
     hence Sq_Circ".p=0.REAL 2 by A1,A2,FUNCT_1:56;
    end;
    hereby assume A3:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) &
       p<>0.REAL 2;
        set q=p;
        set px=|[q`1*sqrt(1+(q`2/q`1)^2),q`2*sqrt(1+(q`2/q`1)^2)]|;
        A4: px`1 = q`1*sqrt(1+(q`2/q`1)^2) &
         px`2 = q`2*sqrt(1+(q`2/q`1)^2) by EUCLID:56;
          1+(q`2/q`1)^2>0 by Lm1;
        then A5:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
        then A6:px`2/px`1=q`2/q`1 by A4,XCMPLX_1:92;
        A7:now assume A8: px`1=0 & px`2=0;
          then A9:q`1=0 by A4,A5,XCMPLX_1:6;
            q`2=0 by A4,A5,A8,XCMPLX_1:6;
         hence contradiction by A3,A9,EUCLID:57,58;
        end;
          q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 &
        q`2*sqrt(1+(q`2/q`1)^2) <= (-q`1)*sqrt(1+(q`2/q`1)^2)
                             by A3,A5,AXIOMS:25;
        then q`2<=q`1 & (-q`1)*sqrt(1+(q`2/q`1)^2) <= q`2*sqrt(1+(q`2/q`1)^2)
           or px`2>=px`1 & px`2<=-px`1 by A4,A5,AXIOMS:25,XCMPLX_1:175;
        then q`2*sqrt(1+(q`2/q`1)^2) <= q`1*sqrt(1+(q`2/q`1)^2) & -px`1<=px`2
           or px`2>=px`1 & px`2<=-px`1 by A4,A5,AXIOMS:25,XCMPLX_1:175;
    then A10:Sq_Circ.px=|[px`1/sqrt(1+(px`2/px`1)^2),px`2/sqrt(1+(px`2/px`1)^2)
]|
                                 by A4,A7,Def1,JGRAPH_2:11;
        A11:px`1/sqrt(1+(px`2/px`1)^2)=q`1 by A4,A5,A6,XCMPLX_1:90;
         px`2/sqrt(1+(px`2/px`1)^2)=q`2 by A4,A5,A6,XCMPLX_1:90;
        then A12:q=Sq_Circ.px by A10,A11,EUCLID:57;
          dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
     hence (Sq_Circ").p=|[p`1*sqrt(1+(p`2/p`1)^2),p`2*sqrt(1+(p`2/p`1)^2)]|
                           by A12,FUNCT_1:56;
    end;
    assume A13: not(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)&
       p<>0.REAL 2;
        then A14: p<>0.REAL 2 & (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
                by JGRAPH_2:23;
        set q=p;
        set px=|[q`1*sqrt(1+(q`1/q`2)^2),q`2*sqrt(1+(q`1/q`2)^2)]|;
        A15: px`2 = q`2*sqrt(1+(q`1/q`2)^2) &
         px`1 = q`1*sqrt(1+(q`1/q`2)^2) by EUCLID:56;
          1+(q`1/q`2)^2>0 by Lm1;
        then A16:sqrt(1+(q`1/q`2)^2)>0 by SQUARE_1:93;
        then A17:px`1/px`2=q`1/q`2 by A15,XCMPLX_1:92;
        A18:now assume A19: px`2=0 & px`1=0;
          then q`2=0 by A15,A16,XCMPLX_1:6;
         hence contradiction by A13,A15,A16,A19,XCMPLX_1:6;
        end;
          q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 &
        q`1*sqrt(1+(q`1/q`2)^2) <= (-q`2)*sqrt(1+(q`1/q`2)^2)
                             by A14,A16,AXIOMS:25;
        then q`1<=q`2 & (-q`2)*sqrt(1+(q`1/q`2)^2) <= q`1*sqrt(1+(q`1/q`2)^2)
           or px`1>=px`2 & px`1<=-px`2 by A15,A16,AXIOMS:25,XCMPLX_1:175;
        then q`1*sqrt(1+(q`1/q`2)^2) <= q`2*sqrt(1+(q`1/q`2)^2) & -px`2<=px`1
           or px`1>=px`2 & px`1<=-px`2 by A15,A16,AXIOMS:25,XCMPLX_1:175;
    then A20:Sq_Circ.px=|[px`1/sqrt(1+(px`1/px`2)^2),px`2/sqrt(1+(px`1/px`2)^2)
]|
                                 by A15,A18,Th14,JGRAPH_2:11;
        A21:px`2/sqrt(1+(px`1/px`2)^2)=q`2 by A15,A16,A17,XCMPLX_1:90;
         px`1/sqrt(1+(px`1/px`2)^2)=q`1 by A15,A16,A17,XCMPLX_1:90;
        then A22:q=Sq_Circ.px by A20,A21,EUCLID:57;
          dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
     hence thesis by A22,FUNCT_1:56;
  end;

theorem Th39: Sq_Circ" is map of TOP-REAL 2,TOP-REAL 2
proof
    A1:dom (Sq_Circ")=rng (Sq_Circ) by FUNCT_1:55;
      the carrier of TOP-REAL 2 c= rng Sq_Circ
     proof let y be set;assume y in the carrier of TOP-REAL 2;
       then reconsider py=y as Point of TOP-REAL 2;
       A2:dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
         now per cases;
       case py=0.REAL 2; then Sq_Circ.py=py by Def1;
        hence ex x being set st x in dom Sq_Circ & y=Sq_Circ.x by A2;
       case A3:(py`2<=py`1 & -py`1<=py`2 or py`2>=py`1 & py`2<=-py`1) &
          py<>0.REAL 2;
        set q=py;
        set px=|[q`1*sqrt(1+(q`2/q`1)^2),q`2*sqrt(1+(q`2/q`1)^2)]|;
        A4: px`1 = q`1*sqrt(1+(q`2/q`1)^2) &
         px`2 = q`2*sqrt(1+(q`2/q`1)^2) by EUCLID:56;
          1+(q`2/q`1)^2>0 by Lm1;
        then A5:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
        then A6:px`2/px`1=q`2/q`1 by A4,XCMPLX_1:92;
        A7:now assume px`1=0 & px`2=0;
          then A8:q`1*sqrt(1+(q`2/q`1)^2)=0 & q`2*sqrt(1+(q`2/q`1)^2)=0
          by EUCLID:56;
          then A9:q`1=0 by A5,XCMPLX_1:6;
            q`2=0 by A5,A8,XCMPLX_1:6;
         hence contradiction by A3,A9,EUCLID:57,58;
        end;
          q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 &
        q`2*sqrt(1+(q`2/q`1)^2) <= (-q`1)*sqrt(1+(q`2/q`1)^2)
                             by A3,A5,AXIOMS:25;
        then q`2<=q`1 & (-q`1)*sqrt(1+(q`2/q`1)^2) <= q`2*sqrt(1+(q`2/q`1)^2)
           or px`2>=px`1 & px`2<=-px`1 by A4,A5,AXIOMS:25,XCMPLX_1:175;
        then q`2*sqrt(1+(q`2/q`1)^2) <= q`1*sqrt(1+(q`2/q`1)^2) & -px`1<=px`2
           or px`2>=px`1 & px`2<=-px`1 by A4,A5,AXIOMS:25,XCMPLX_1:175;
    then A10:Sq_Circ.px=|[px`1/sqrt(1+(px`2/px`1)^2),px`2/sqrt(1+(px`2/px`1)^2)
]|
                                 by A4,A7,Def1,JGRAPH_2:11;
        A11:px`1/sqrt(1+(px`2/px`1)^2)=q`1 by A4,A5,A6,XCMPLX_1:90;
         px`2/sqrt(1+(px`2/px`1)^2)=q`2 by A4,A5,A6,XCMPLX_1:90;
        then A12:q=Sq_Circ.px by A10,A11,EUCLID:57;
          dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
        hence ex x being set st x in dom Sq_Circ & y=Sq_Circ.x by A12;
       case A13: not(py`2<=py`1 & -py`1<=py`2 or py`2>=py`1 & py`2<=-py`1)&
       py<>0.REAL 2;
        then A14: py<>0.REAL 2 & (py`1<=py`2 & -py`2<=py`1 or
             py`1>=py`2 & py`1<=-py`2) by JGRAPH_2:23;
        set q=py;
        set px=|[q`1*sqrt(1+(q`1/q`2)^2),q`2*sqrt(1+(q`1/q`2)^2)]|;
        A15: px`2 = q`2*sqrt(1+(q`1/q`2)^2) &
         px`1 = q`1*sqrt(1+(q`1/q`2)^2) by EUCLID:56;
          1+(q`1/q`2)^2>0 by Lm1;
        then A16:sqrt(1+(q`1/q`2)^2)>0 by SQUARE_1:93;
        then A17:px`1/px`2=q`1/q`2 by A15,XCMPLX_1:92;
        A18: now assume A19: px`2=0 & px`1=0;
          then q`2=0 by A15,A16,XCMPLX_1:6;
         hence contradiction by A13,A15,A16,A19,XCMPLX_1:6;
        end;
          q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 &
        q`1*sqrt(1+(q`1/q`2)^2) <= (-q`2)*sqrt(1+(q`1/q`2)^2)
                             by A14,A16,AXIOMS:25;
        then q`1<=q`2 & (-q`2)*sqrt(1+(q`1/q`2)^2) <= q`1*sqrt(1+(q`1/q`2)^2)
           or px`1>=px`2 & px`1<=-px`2 by A15,A16,AXIOMS:25,XCMPLX_1:175;
        then q`1*sqrt(1+(q`1/q`2)^2) <= q`2*sqrt(1+(q`1/q`2)^2) & -px`2<=px`1
           or px`1>=px`2 & px`1<=-px`2 by A15,A16,AXIOMS:25,XCMPLX_1:175;
     then A20:Sq_Circ.px=|[px`1/sqrt(1+(px`1/px`2)^2),px`2/sqrt(1+(px`1/px`2)^2
)]|
                                 by A15,A18,Th14,JGRAPH_2:11;
        A21:px`2/sqrt(1+(px`1/px`2)^2)=q`2 by A15,A16,A17,XCMPLX_1:90;
         px`1/sqrt(1+(px`1/px`2)^2)=q`1 by A15,A16,A17,XCMPLX_1:90;
        then A22:q=Sq_Circ.px by A20,A21,EUCLID:57;
          dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
        hence ex x being set st x in dom Sq_Circ & y=Sq_Circ.x by A22;
       end;
      hence y in rng Sq_Circ by FUNCT_1:def 5;
     end;
    then A23:dom (Sq_Circ")=the carrier of TOP-REAL 2 by A1,XBOOLE_0:def 10;
      rng (Sq_Circ")=dom (Sq_Circ) by FUNCT_1:55
    .=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
    then Sq_Circ" is Function of
       the carrier of TOP-REAL 2,the carrier of TOP-REAL 2 by A23,FUNCT_2:3;
    hence thesis ;
end;

theorem Th40: for p being Point of TOP-REAL 2 st p<>0.REAL 2 holds
 ((p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) implies
 (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|) &
 (not(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) implies
 (Sq_Circ").p=|[p`1*sqrt(1+(p`2/p`1)^2),p`2*sqrt(1+(p`2/p`1)^2)]|)
proof let p be Point of TOP-REAL 2;assume
   A1: p<>0.REAL 2;
     hereby assume A2:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2);
         now per cases by A2;
       case A3:p`1<=p`2 & -p`2<=p`1;
          now assume A4:p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1;
          A5: now per cases by A4;
           case p`2<=p`1 & -p`1<=p`2;
             hence p`1=p`2 or p`1=-p`2 by A3,AXIOMS:21;
           case p`2>=p`1 & p`2<=-p`1; then -p`2>=--p`1 by REAL_1:50;
            hence p`1=p`2 or p`1=-p`2 by A3,AXIOMS:21;
           end;
             now per cases by A5;
           case p`1=p`2;
            hence (Sq_Circ").p
               =|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|
                                       by A1,A4,Th38;
           case A6:p`1=-p`2;
             A7:now assume A8:p`1=0;
               then p`2=-0 by A6;
              hence contradiction by A1,A8,EUCLID:57,58;
             end;
             A9:-p`1=p`2 by A6;
             then p`1/p`2=-1 by A7,XCMPLX_1:199;
             then A10:(p`1/p`2)^2=1^2 by SQUARE_1:61;
               p`2/p`1=-1 by A7,A9,XCMPLX_1:198;
             then (p`2/p`1)^2=1^2 by SQUARE_1:61;
         hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)
]|
                                             by A1,A4,A10,Th38;
          end;
       hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|;
        end;
       hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|
                                             by A1,Th38;
       case A11:p`1>=p`2 & p`1<=-p`2;
          now assume A12:p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1;
        A13: now per cases by A12;
         case p`2<=p`1 & -p`1<=p`2; then --p`1>=-p`2 by REAL_1:50;
           hence p`1=p`2 or p`1=-p`2 by A11,AXIOMS:21;
         case p`2>=p`1 & p`2<=-p`1;
           hence p`1=p`2 or p`1=-p`2 by A11,AXIOMS:21;
         end;
          now per cases by A13;
        case p`1=p`2;
         hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)
]|
                                     by A1,A12,Th38;
        case A14:p`1=-p`2;
         A15:now assume A16:p`1=0;
          then p`2=-0 by A14 .=0;
          hence contradiction by A1,A16,EUCLID:57,58;
         end;
         A17:-p`1=p`2 by A14;
          p`2<>0 by A14,A15;
         then p`1/p`2=-1 by A14,XCMPLX_1:198;
         then A18:(p`1/p`2)^2=1^2 by SQUARE_1:61;
           p`2/p`1=-1 by A15,A17,XCMPLX_1:198;
         then (p`2/p`1)^2=1^2 by SQUARE_1:61;
         hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)
]|
                                        by A1,A12,A18,Th38;
        end;
        hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|
;
        end;
        hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|
                                               by A1,Th38;
       end;
      hence (Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|;
     end;
     assume
       A19:not(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2);
       A20:-p`2<p`1 implies --p`2>-p`1 by REAL_1:50;
         -p`2>p`1 implies --p`2<-p`1 by REAL_1:50;
     hence thesis by A1,A19,A20,Th38;
end;

theorem Th41: for X being non empty TopSpace,
f1,f2 being map of X,R^1 st f1 is continuous & f2 is continuous &
(for q being Point of X holds f2.q<>0)
holds ex g being map of X,R^1
st (for p being Point of X,r1,r2 being real number st
f1.p=r1 & f2.p=r2 holds g.p=r1*sqrt(1+(r1/r2)^2)) & g is continuous
proof let X be non empty TopSpace, f1,f2 be map of X,R^1;
assume A1:f1 is continuous & f2 is continuous
& (for q being Point of X holds f2.q<>0);
then consider g2 being map of X,R^1
  such that A2: (for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g2.p=sqrt(1+(r1/r2)^2)) & g2 is continuous by Th18;
consider g3 being map of X,R^1
  such that A3: (for p being Point of X,r1,r0 being real number st
 f1.p=r1 & g2.p=r0 holds g3.p=r1*r0) & g3 is continuous by A1,A2,JGRAPH_2:35;
  for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g3.p=r1*sqrt(1+(r1/r2)^2)
  proof let p be Point of X,r1,r2 be real number;
   assume A4:f1.p=r1 & f2.p=r2;
    then g2.p=sqrt(1+(r1/r2)^2) by A2;
   hence thesis by A3,A4;
  end;
hence thesis by A3;
end;

theorem Th42: for X being non empty TopSpace,
f1,f2 being map of X,R^1 st f1 is continuous & f2 is continuous &
(for q being Point of X holds f2.q<>0)
ex g being map of X,R^1 st (for p being Point of X,r1,r2 being real number st
f1.p=r1 & f2.p=r2 holds g.p=r2*sqrt(1+(r1/r2)^2)) & g is continuous
proof let X be non empty TopSpace,
f1,f2 be map of X,R^1;
assume A1:f1 is continuous & f2 is continuous
& (for q being Point of X holds f2.q<>0);
then consider g2 being map of X,R^1
  such that A2: (for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g2.p=sqrt(1+(r1/r2)^2)) & g2 is continuous by Th18;
consider g3 being map of X,R^1
  such that A3: (for p being Point of X,r2,r0 being real number st
 f2.p=r2 & g2.p=r0 holds g3.p=r2*r0) & g3 is continuous by A1,A2,JGRAPH_2:35;
  for p being Point of X,r1,r2 being real number st
  f1.p=r1 & f2.p=r2 holds g3.p=r2*sqrt(1+(r1/r2)^2)
  proof let p be Point of X,r1,r2 be real number;
   assume A4:f1.p=r1 & f2.p=r2;
    then g2.p=sqrt(1+(r1/r2)^2) by A2;
   hence thesis by A3,A4;
  end;
hence thesis by A3;
end;

theorem Th43: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1*sqrt(1+(p`2/p`1)^2)) & (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0 ) holds
f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1*sqrt(1+(p`2/p`1)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    for q being Point of (TOP-REAL 2)|K1 holds g1.q<>0
  proof let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g1.q=proj1.q by Lm6 .=q2`1 by PSCOMP_1:def 28;
   hence g1.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g2.q=r1 & g1.q=r2
  holds g3.q=r2*sqrt(1+(r1/r2)^2)) & g3 is continuous by Th42;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
     now let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`1*sqrt(1+(r`2/r`1)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence thesis by A3,A4,FUNCT_1:9;
end;

theorem Th44: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2*sqrt(1+(p`2/p`1)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0) holds f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2*sqrt(1+(p`2/p`1)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    for q being Point of (TOP-REAL 2)|K1 holds g1.q<>0
  proof let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g1.q=proj1.q by Lm6 .=q2`1 by PSCOMP_1:def 28;
   hence g1.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g2.q=r1 & g1.q=r2
  holds g3.q=r1*sqrt(1+(r1/r2)^2)) & g3 is continuous by Th41;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
     now let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`2*sqrt(1+(r`2/r`1)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence thesis by A3,A4,FUNCT_1:9;
end;

theorem Th45: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2*sqrt(1+(p`1/p`2)^2)) & (for q being Point of TOP-REAL 2 st
q in the carrier of (TOP-REAL 2)|K1 holds q`2<>0 ) holds
f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`2*sqrt(1+(p`1/p`2)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    for q being Point of (TOP-REAL 2)|K1 holds g2.q<>0
  proof let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g2.q=proj2.q by Lm4 .=q2`2 by PSCOMP_1:def 29;
   hence g2.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g1.q=r1 & g2.q=r2
  holds g3.q=r2*sqrt(1+(r1/r2)^2)) & g3 is continuous by Th42;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
     now let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`2*sqrt(1+(r`1/r`2)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence thesis by A3,A4,FUNCT_1:9;
end;

theorem Th46: for K1 being non empty Subset of TOP-REAL 2,
f being map of (TOP-REAL 2)|K1,R^1 st
(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1*sqrt(1+(p`1/p`2)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0 ) holds
f is continuous
proof let K1 be non empty Subset of TOP-REAL 2,
f be map of (TOP-REAL 2)|K1,R^1;
assume
A1:(for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f.p=p`1*sqrt(1+(p`1/p`2)^2)) &
  (for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0 );
  A2: the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
  reconsider g2=proj2|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm5;
  reconsider g1=proj1|K1 as continuous map of (TOP-REAL 2)|K1,R^1 by Lm7;
    for q being Point of (TOP-REAL 2)|K1 holds g2.q<>0
  proof let q be Point of (TOP-REAL 2)|K1;
      q in the carrier of (TOP-REAL 2)|K1;
    then reconsider q2=q as Point of TOP-REAL 2 by A2;
      g2.q=proj2.q by Lm4 .=q2`2 by PSCOMP_1:def 29;
   hence g2.q<>0 by A1;
  end;
  then consider g3 being map of (TOP-REAL 2)|K1,R^1 such that
  A3: (for q being Point of
  (TOP-REAL 2)|K1,r1,r2 being real number st g1.q=r1 & g2.q=r2
  holds g3.q=r1*sqrt(1+(r1/r2)^2)) & g3 is continuous by Th41;
   dom g3=the carrier of (TOP-REAL 2)|K1 by FUNCT_2:def 1;
  then A4:dom f=dom g3 by FUNCT_2:def 1;
     now let x be set;assume
     A5:x in dom f;
     then x in the carrier of (TOP-REAL 2)|K1;
     then x in K1 by JORDAN1:1;
     then reconsider r=x as Point of (TOP-REAL 2);
     reconsider s=x as Point of (TOP-REAL 2)|K1 by A5;
     A6:f.r=r`1*sqrt(1+(r`1/r`2)^2) by A1,A5;
     A7:g2.s=proj2.s by Lm4;
     A8:g1.s=proj1.s by Lm6;
     A9:proj2.r=r`2 by PSCOMP_1:def 29;
       proj1.r=r`1 by PSCOMP_1:def 28;
    hence f.x=g3.x by A3,A6,A7,A8,A9;
   end;
hence thesis by A3,A4,FUNCT_1:9;
end;

Lm13: for K1 being non empty Subset of TOP-REAL 2 holds
  (proj2)*((Sq_Circ")|K1) is map of (TOP-REAL 2)|K1,R^1
proof
 let K1 be non empty Subset of TOP-REAL 2;
A1:dom ((proj2)*((Sq_Circ")|K1)) c= dom ((Sq_Circ")|K1) by RELAT_1:44;
  dom ((Sq_Circ")|K1) c= dom ((proj2)*((Sq_Circ")|K1))
proof let x be set;assume A2:x in dom ((Sq_Circ")|K1);
   then A3:x in dom (Sq_Circ") /\ K1 by FUNCT_1:68;
   A4:((Sq_Circ")|K1).x=(Sq_Circ").x by A2,FUNCT_1:68;
     x in dom (Sq_Circ") by A3,XBOOLE_0:def 3;
   then A5:(Sq_Circ").x in rng (Sq_Circ") by FUNCT_1:12;
     rng (Sq_Circ") c= the carrier of TOP-REAL 2 by Th39,RELSET_1:12;
  hence thesis by A2,A4,A5,Lm3,FUNCT_1:21;
end;
then A6: dom ((proj2)*((Sq_Circ")|K1))=dom ((Sq_Circ")|K1) by A1,XBOOLE_0:def
10
  .=dom (Sq_Circ") /\ K1 by FUNCT_1:68
  .=(the carrier of TOP-REAL 2)/\ K1 by Th39,FUNCT_2:def 1
  .=K1 by XBOOLE_1:28
  .=the carrier of (TOP-REAL 2)|K1 by JORDAN1:1;
A7:rng ((proj2)*((Sq_Circ")|K1)) c= rng (proj2) by RELAT_1:45;
    rng proj2 c= the carrier of R^1 by JGRAPH_2:17,RELSET_1:12;
  then rng ((proj2)*((Sq_Circ")|K1)) c= the carrier of R^1 by A7,XBOOLE_1:1;
  then (proj2)*((Sq_Circ")|K1) is Function of the carrier of (TOP-REAL 2)|K1,
  the carrier of R^1 by A6,FUNCT_2:4;
  hence thesis ;
end;

Lm14: for K1 being non empty Subset of TOP-REAL 2 holds
  (proj1)*((Sq_Circ")|K1) is map of (TOP-REAL 2)|K1,R^1
proof
 let K1 be non empty Subset of TOP-REAL 2;
A1:dom ((proj1)*((Sq_Circ")|K1)) c= dom ((Sq_Circ")|K1) by RELAT_1:44;
     dom ((Sq_Circ")|K1) c= dom ((proj1)*((Sq_Circ")|K1))
proof let x be set;assume A2:x in dom ((Sq_Circ")|K1);
   then A3:x in dom (Sq_Circ") /\ K1 by FUNCT_1:68;
   A4:((Sq_Circ")|K1).x=(Sq_Circ").x by A2,FUNCT_1:68;
     x in dom (Sq_Circ") by A3,XBOOLE_0:def 3;
   then A5:(Sq_Circ").x in rng (Sq_Circ") by FUNCT_1:12;
     rng (Sq_Circ") c= the carrier of TOP-REAL 2 by Th39,RELSET_1:12;
  hence thesis by A2,A4,A5,Lm3,FUNCT_1:21;
end;
then A6:dom ((proj1)*((Sq_Circ")|K1)) =dom ((Sq_Circ")|K1) by A1,XBOOLE_0:def
10
.=dom (Sq_Circ") /\ K1 by FUNCT_1:68
.=((the carrier of TOP-REAL 2))/\ K1 by Th39,FUNCT_2:def 1
.=K1 by XBOOLE_1:28
.=the carrier of (TOP-REAL 2)|K1 by JORDAN1:1;
A7:rng ((proj1)*((Sq_Circ")|K1)) c= rng (proj1) by RELAT_1:45;
  rng proj1 c= the carrier of R^1 by JGRAPH_2:16,RELSET_1:12;
then rng ((proj1)*((Sq_Circ")|K1)) c= the carrier of R^1 by A7,XBOOLE_1:1;
then (proj1)*((Sq_Circ")|K1) is Function of the carrier of (TOP-REAL 2)|K1,
the carrier of R^1 by A6,FUNCT_2:4;
hence thesis ;
end;

theorem Th47: for K0,B0 being Subset of TOP-REAL 2,f being
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0
st f=(Sq_Circ")|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2}
holds f is continuous
proof let K0,B0 be Subset of TOP-REAL 2,f be
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0;
assume A1:f=(Sq_Circ")|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2};
then 1.REAL 2 in K0 by Lm8;
then reconsider K1=K0 as non empty Subset of TOP-REAL 2;
reconsider g2=(proj2)*((Sq_Circ")|K1) as map of (TOP-REAL 2)|K1,R^1 by Lm13;
reconsider g1=(proj1)*((Sq_Circ")|K1) as map of (TOP-REAL 2)|K1,R^1 by Lm14;
A2: for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`1<>0
   proof let q be Point of TOP-REAL 2;
    assume A3:q in the carrier of (TOP-REAL 2)|K1;
        the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A4: q=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A3;
       now assume A5:q`1=0;
        then q`2=0 by A4;
      hence contradiction by A4,A5,EUCLID:57,58;
     end;
    hence q`1<>0;
   end;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g2.p=p`2*sqrt(1+(p`2/p`1)^2)
   proof let p be Point of TOP-REAL 2;
    assume A6: p in the carrier of (TOP-REAL 2)|K1;
     A7:dom ((Sq_Circ")|K1)=dom (Sq_Circ") /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by Th39,FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A8:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A9: p=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A6;
     A10:(Sq_Circ").p
     =|[p`1*sqrt(1+(p`2/p`1)^2),p`2*sqrt(1+(p`2/p`1)^2)]| by A9,Th38;
      ((Sq_Circ")|K1).p=(Sq_Circ").p by A6,A8,FUNCT_1:72;
     then g2.p=(proj2).(|[p`1*sqrt(1+(p`2/p`1)^2),p`2*sqrt(1+(p`2/p`1)^2)]|)
                             by A6,A7,A8,A10,FUNCT_1:23
      .=(|[p`1*sqrt(1+(p`2/p`1)^2),
        p`2*sqrt(1+(p`2/p`1)^2)]|)`2 by PSCOMP_1:def 29
      .=p`2*sqrt(1+(p`2/p`1)^2) by EUCLID:56;
    hence thesis;
   end;
then consider f2 being map of (TOP-REAL 2)|K1,R^1 such that
  A11:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f2.p=p`2*sqrt(1+(p`2/p`1)^2);
A12:f2 is continuous by A2,A11,Th44;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g1.p=p`1*sqrt(1+(p`2/p`1)^2)
   proof let p be Point of TOP-REAL 2;
    assume A13: p in the carrier of (TOP-REAL 2)|K1;
     A14:dom ((Sq_Circ")|K1)=dom (Sq_Circ") /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by Th39,FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A15:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A16: p=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A13;
     A17:(Sq_Circ").p=|[p`1*sqrt(1+(p`2/p`1)^2),
               p`2*sqrt(1+(p`2/p`1)^2)]| by A16,Th38;
      ((Sq_Circ")|K1).p=(Sq_Circ").p by A13,A15,FUNCT_1:72;
     then g1.p=(proj1).(|[p`1*sqrt(1+(p`2/p`1)^2),
          p`2*sqrt(1+(p`2/p`1)^2)]|)
                             by A13,A14,A15,A17,FUNCT_1:23
        .=(|[p`1*sqrt(1+(p`2/p`1)^2),
           p`2*sqrt(1+(p`2/p`1)^2)]|)`1 by PSCOMP_1:def 28
        .=p`1*sqrt(1+(p`2/p`1)^2) by EUCLID:56;
    hence thesis;
   end;
then consider f1 being map of (TOP-REAL 2)|K1,R^1 such that
  A18:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f1.p=p`1*sqrt(1+(p`2/p`1)^2);
A19:f1 is continuous by A2,A18,Th43;
    now let x,y,r,s be real number;
   assume A20: |[x,y]| in K1 & r=f1.(|[x,y]|) & s=f2.(|[x,y]|);
     set p99=|[x,y]|;
     A21:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     consider p3 being Point of TOP-REAL 2 such that
     A22: p99=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A1,A20;
     A23:f1.p99=p99`1*sqrt(1+(p99`2/p99`1)^2) by A18,A20,A21;
      ((Sq_Circ")|K0).(|[x,y]|)=((Sq_Circ")).(|[x,y]|) by A20,FUNCT_1:72
    .= |[p99`1*sqrt(1+(p99`2/p99`1)^2),
    p99`2*sqrt(1+(p99`2/p99`1)^2)]| by A22,Th38
    .=|[r,s]| by A11,A20,A21,A23;
   hence f.(|[x,y]|)=|[r,s]| by A1;
  end;
hence thesis by A1,A12,A19,Lm11,JGRAPH_2:45;
end;

theorem Th48: for K0,B0 being Subset of TOP-REAL 2,f being
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0
st f=(Sq_Circ")|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2}
holds f is continuous
proof let K0,B0 be Subset of TOP-REAL 2,f be
map of (TOP-REAL 2)|K0,(TOP-REAL 2)|B0;
assume A1:f=(Sq_Circ")|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2} &
K0={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2};
     then 1.REAL 2 in K0 by Lm12;
then reconsider K1=K0 as non empty Subset of TOP-REAL 2;
reconsider g2=(proj1)*((Sq_Circ")|K1) as map of (TOP-REAL 2)|K1,R^1 by Lm14;
reconsider g1=(proj2)*((Sq_Circ")|K1) as map of (TOP-REAL 2)|K1,R^1 by Lm13;
A2: for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K1 holds q`2<>0
   proof let q be Point of TOP-REAL 2;
    assume A3:q in the carrier of (TOP-REAL 2)|K1;
       the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A4: q=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A3;
       now assume A5:q`2=0;
        then q`1=0 by A4;
      hence contradiction by A4,A5,EUCLID:57,58;
     end;
    hence q`2<>0;
   end;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g2.p=p`1*sqrt(1+(p`1/p`2)^2)
   proof let p be Point of TOP-REAL 2;
    assume A6: p in the carrier of (TOP-REAL 2)|K1;
     A7:dom ((Sq_Circ")|K1)=dom (Sq_Circ") /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by Th39,FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A8:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A9: p=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A6;
     A10:(Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),
         p`2*sqrt(1+(p`1/p`2)^2)]| by A9,Th40;
      ((Sq_Circ")|K1).p=(Sq_Circ").p by A6,A8,FUNCT_1:72;
     then g2.p=(proj1).(|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|)
                             by A6,A7,A8,A10,FUNCT_1:23
        .=(|[p`1*sqrt(1+(p`1/p`2)^2),
            p`2*sqrt(1+(p`1/p`2)^2)]|)`1 by PSCOMP_1:def 28
        .=p`1*sqrt(1+(p`1/p`2)^2) by EUCLID:56;
    hence g2.p=p`1*sqrt(1+(p`1/p`2)^2);
   end;
then consider f2 being map of (TOP-REAL 2)|K1,R^1 such that
  A11:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f2.p=p`1*sqrt(1+(p`1/p`2)^2);
A12:f2 is continuous by A2,A11,Th46;
    for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds g1.p=p`2*sqrt(1+(p`1/p`2)^2)
   proof let p be Point of TOP-REAL 2;
    assume A13: p in the carrier of (TOP-REAL 2)|K1;
     A14:dom ((Sq_Circ")|K1)=dom (Sq_Circ") /\ K1 by FUNCT_1:68
     .=((the carrier of TOP-REAL 2))/\ K1 by Th39,FUNCT_2:def 1
     .=K1 by XBOOLE_1:28;
     A15:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A16: p=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A13;
     A17:(Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),
           p`2*sqrt(1+(p`1/p`2)^2)]| by A16,Th40;
      ((Sq_Circ")|K1).p=(Sq_Circ").p by A13,A15,FUNCT_1:72;
     then g1.p=(proj2).(|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|)
                             by A13,A14,A15,A17,FUNCT_1:23
        .=(|[p`1*sqrt(1+(p`1/p`2)^2),
          p`2*sqrt(1+(p`1/p`2)^2)]|)`2 by PSCOMP_1:def 29
        .=p`2*sqrt(1+(p`1/p`2)^2) by EUCLID:56;
    hence g1.p=p`2*sqrt(1+(p`1/p`2)^2);
   end;
then consider f1 being map of (TOP-REAL 2)|K1,R^1 such that
  A18:for p being Point of TOP-REAL 2 st p in the carrier of (TOP-REAL 2)|K1
  holds f1.p=p`2*sqrt(1+(p`1/p`2)^2);
A19:f1 is continuous by A2,A18,Th45;
  for x,y,s,r being real number st |[x,y]| in K1 &
  s=f2.(|[x,y]|) & r=f1.(|[x,y]|) holds f.(|[x,y]|)=|[s,r]|
  proof let x,y,s,r be real number;
   assume A20: |[x,y]| in K1 & s=f2.(|[x,y]|) & r=f1.(|[x,y]|);
     set p99=|[x,y]|;
     A21:the carrier of (TOP-REAL 2)|K1=K1 by JORDAN1:1;
     consider p3 being Point of TOP-REAL 2 such that
     A22: p99=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A1,A20;
     A23:f1.p99=p99`2*sqrt(1+(p99`1/p99`2)^2) by A18,A20,A21;
      ((Sq_Circ")|K0).(|[x,y]|)=((Sq_Circ")).(|[x,y]|) by A20,FUNCT_1:72
    .= |[p99`1*sqrt(1+(p99`1/p99`2)^2),
       p99`2*sqrt(1+(p99`1/p99`2)^2)]| by A22,Th40
    .=|[s,r]| by A11,A20,A21,A23;
   hence f.(|[x,y]|)=|[s,r]| by A1;
  end;
hence thesis by A1,A12,A19,Lm11,JGRAPH_2:45;
end;

theorem Th49: for B0 being Subset of TOP-REAL 2,K0 being Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0)
st f=(Sq_Circ")|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2}
& K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2}
holds f is continuous & K0 is closed
proof let B0 be Subset of TOP-REAL 2,K0 be Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0);
defpred P0[Point of TOP-REAL 2] means
($1`2<=$1`1 & -$1`1<=$1`2 or $1`2>=$1`1 & $1`2<=-$1`1);
set k0 = {p:P0[p] & p<>0.REAL 2};
set b0 = (the carrier of TOP-REAL 2) \ {0.REAL 2};
assume A1: f=(Sq_Circ")|K0 & B0=b0 & K0=k0;
    the carrier of (TOP-REAL 2)|B0 = B0 by JORDAN1:1;
  then K0 c= the carrier of TOP-REAL 2 by XBOOLE_1:1;
  then reconsider K1=K0 as Subset of TOP-REAL 2;
    k0 c= (the carrier of TOP-REAL 2) \ {0.REAL 2} from TopIncl;
  then A2: ((TOP-REAL 2)|B0)|K0=(TOP-REAL 2)|K1 by A1,JORDAN6:47;
  defpred P[Point of TOP-REAL 2] means
  ($1`2<=$1`1 & -$1`1<=$1`2 or $1`2>=$1`1 & $1`2<=-$1`1);
  reconsider K1={p7 where p7 is Point of TOP-REAL 2: P[p7]}
  as Subset of TOP-REAL 2 from TopSubset;
  reconsider K2={p7 where p7 is Point of TOP-REAL 2:p7`2<=p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K3 = {p7 where p7 is Point of TOP-REAL 2:-p7`1<=p7`2 }
    as closed Subset of TOP-REAL 2 by JGRAPH_2:57;
  reconsider K4={p7 where p7 is Point of TOP-REAL 2: p7`1<=p7`2 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K5={p7 where p7 is Point of TOP-REAL 2:p7`2<=-p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:57;
  A3:K2 /\ K3 is closed by TOPS_1:35;
  A4:K4 /\ K5 is closed by TOPS_1:35;
  A5:K2 /\ K3 \/ K4 /\ K5 c= K1
  proof let x be set;assume
    A6:x in K2 /\ K3 \/ K4 /\ K5;
    per cases by A6,XBOOLE_0:def 2;
    suppose x in K2 /\ K3;
      then A7:x in K2 & x in K3 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A8: p7=x & p7`2<=(p7`1);
      consider p8 being Point of TOP-REAL 2 such that
      A9: p8=x & -p8`1<=p8`2 by A7;
     thus x in K1 by A8,A9;
    suppose x in K4 /\ K5;
      then A10:x in K4 & x in K5 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A11: p7=x & p7`2>=(p7`1);
      consider p8 being Point of TOP-REAL 2 such that
      A12: p8=x & p8`2<= -p8`1 by A10;
     thus x in K1 by A11,A12;
  end;
    K1 c= K2 /\ K3 \/ K4 /\ K5
   proof let x be set;assume x in K1;
     then consider p being Point of TOP-REAL 2 such that
     A13: p=x & (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1);
       x in K2 & x in K3 or x in K4 & x in K5 by A13;
     then x in K2 /\ K3 or x in K4 /\ K5 by XBOOLE_0:def 3;
    hence x in K2 /\ K3 \/ K4 /\ K5 by XBOOLE_0:def 2;
   end;
  then K1=K2 /\ K3 \/ K4 /\ K5 by A5,XBOOLE_0:def 10;
  then A14:K1 is closed by A3,A4,TOPS_1:36;
    k0={p7 where p7 is Point of TOP-REAL 2:P0[p7]} /\ b0
  from TopInter;
  then K0=K1 /\ [#]((TOP-REAL 2)|B0) by A1,PRE_TOPC:def 10;
  hence thesis by A1,A2,A14,Th47,PRE_TOPC:43;
end;

theorem Th50: for B0 being Subset of TOP-REAL 2,K0 being Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0)
st f=(Sq_Circ")|K0 & B0=(the carrier of TOP-REAL 2) \ {0.REAL 2}
& K0={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2}
holds f is continuous & K0 is closed
proof let B0 be Subset of TOP-REAL 2,K0 be Subset of
(TOP-REAL 2)|B0,f being map of ((TOP-REAL 2)|B0)|K0,((TOP-REAL 2)|B0);
  defpred P0[Point of TOP-REAL 2] means
  ($1`1<=$1`2 & -$1`2<=$1`1 or $1`1>=$1`2 & $1`1<=-$1`2);
set k0 = {p:P0[p] & p<>0.REAL 2},
    b0=(the carrier of TOP-REAL 2) \ {0.REAL 2};
assume A1: f=(Sq_Circ")|K0 & B0=b0 & K0=k0;
    the carrier of (TOP-REAL 2)|B0= B0 by JORDAN1:1;
  then K0 c= the carrier of TOP-REAL 2 by XBOOLE_1:1;
  then reconsider K1=K0 as Subset of TOP-REAL 2;
  defpred P[Point of TOP-REAL 2] means
  ($1`1<=$1`2 & -$1`2<=$1`1 or $1`1>=$1`2 & $1`1<=-$1`2);
    {p:P[p] & p<>0.REAL 2} c=
    (the carrier of TOP-REAL 2) \ {0.REAL 2} from TopIncl;
  then A2: ((TOP-REAL 2)|B0)|K0=(TOP-REAL 2)|K1 by A1,JORDAN6:47;
  set k1 = {p7 where p7 is Point of TOP-REAL 2: P0[p7]};
  reconsider K1=k1 as Subset of TOP-REAL 2 from TopSubset;
  reconsider K2={p7 where p7 is Point of TOP-REAL 2:p7`1<=p7`2 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K3={p7 where p7 is Point of TOP-REAL 2:-p7`2<=p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:58;
  reconsider K4={p7 where p7 is Point of TOP-REAL 2:p7`2<=p7`1 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:56;
  reconsider K5={p7 where p7 is Point of TOP-REAL 2:p7`1<=-p7`2 }
  as closed Subset of TOP-REAL 2 by JGRAPH_2:58;
  A3:K2 /\ K3 is closed by TOPS_1:35;
  A4:K4 /\ K5 is closed by TOPS_1:35;
  A5:K2 /\ K3 \/ K4 /\ K5 c= K1
  proof let x be set;assume
    A6:x in K2 /\ K3 \/ K4 /\ K5;
    per cases by A6,XBOOLE_0:def 2;
    suppose x in K2 /\ K3;
      then A7:x in K2 & x in K3 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A8: p7=x & p7`1<=(p7`2);
      consider p8 being Point of TOP-REAL 2 such that
      A9: p8=x & -p8`2<=p8`1 by A7;
     thus x in K1 by A8,A9;
    suppose x in K4 /\ K5;
      then A10:x in K4 & x in K5 by XBOOLE_0:def 3;
      then consider p7 being Point of TOP-REAL 2 such that
      A11: p7=x & p7`1>=(p7`2);
      consider p8 being Point of TOP-REAL 2 such that
      A12: p8=x & p8`1<= -p8`2 by A10;
     thus x in K1 by A11,A12;
  end;
    K1 c= K2 /\ K3 \/ K4 /\ K5
   proof let x be set;assume x in K1;
     then consider p being Point of TOP-REAL 2 such that
     A13: p=x &
      (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2);
       x in K2 & x in K3 or x in K4 & x in K5 by A13;
     then x in K2 /\ K3 or x in K4 /\ K5 by XBOOLE_0:def 3;
    hence x in K2 /\ K3 \/ K4 /\ K5 by XBOOLE_0:def 2;
   end;
  then K1=K2 /\ K3 \/ K4 /\ K5 by A5,XBOOLE_0:def 10;
  then A14:K1 is closed by A3,A4,TOPS_1:36;
    k0=k1 /\ b0 from TopInter;
  then K0=K1 /\ [#]((TOP-REAL 2)|B0) by A1,PRE_TOPC:def 10;
hence thesis by A1,A2,A14,Th48,PRE_TOPC:43;
end;

theorem Th51:for D being non empty Subset of TOP-REAL 2
st D`={0.REAL 2} holds
ex h being map of (TOP-REAL 2)|D,(TOP-REAL 2)|D
st h=(Sq_Circ")|D & h is continuous
proof let D be non empty Subset of TOP-REAL 2;
assume A1:D`={0.REAL 2};
  set B0 = {0.REAL 2};
  A2: D = (B0)` by A1
     .=((the carrier of TOP-REAL 2)\ {0.REAL 2}) by SUBSET_1:def 5;
    A3:{p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
       & p<>0.REAL 2} c= the carrier of (TOP-REAL 2)|D
       proof let x be set;
        assume x in {p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
       & p<>0.REAL 2};
         then consider p such that A4: x=p &
         (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)& p<>0.REAL 2;
           now assume not x in D;
           then x in (the carrier of TOP-REAL 2) \ D by A4,XBOOLE_0:def 4;
           then x in D` by SUBSET_1:def 5;
          hence contradiction by A1,A4,TARSKI:def 1;
         end;
        hence x in the carrier of (TOP-REAL 2)|D by JORDAN1:1;
       end;
        1.REAL 2 in {p where p is Point of TOP-REAL 2:
        (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2}
        by Lm8;
   then reconsider K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
  & p<>0.REAL 2} as non empty Subset of (TOP-REAL 2)|D by A3;
    A5:{p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
       & p<>0.REAL 2} c= the carrier of (TOP-REAL 2)|D
       proof let x be set;
        assume x in {p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
       & p<>0.REAL 2};
         then consider p such that A6: x=p &
         (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)& p<>0.REAL 2;
           now assume not x in D;
           then x in (the carrier of TOP-REAL 2) \ D by A6,XBOOLE_0:def 4;
           then x in D` by SUBSET_1:def 5;
          hence contradiction by A1,A6,TARSKI:def 1;
         end;
        hence x in the carrier of (TOP-REAL 2)|D by JORDAN1:1;
       end;
     set Y1=|[-1,1]|;
      Y1`1=-1 & Y1`2=1 by EUCLID:56;
     then Y1 in {p where p is Point of TOP-REAL 2:
     (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
       & p<>0.REAL 2} by JGRAPH_2:11;
  then reconsider K1={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
  & p<>0.REAL 2} as non empty Subset of (TOP-REAL 2)|D by A5;
   A7:K0 c= the carrier of TOP-REAL 2
   proof let z be set;assume z in K0;
        then consider p8 being Point of TOP-REAL 2 such that
        A8: p8=z &((p8`2<=p8`1 & -p8`1<=p8`2 or p8`2>=p8`1 & p8`2<=-p8`1)
         & p8<>0.REAL 2);
    thus z in (the carrier of TOP-REAL 2) by A8;
   end;
  A9:dom ((Sq_Circ")|K0)= dom ((Sq_Circ")) /\ K0 by FUNCT_1:68
       .=((the carrier of TOP-REAL 2)) /\ K0 by Th39,FUNCT_2:def 1
       .=K0 by A7,XBOOLE_1:28;
  A10: K0=the carrier of ((TOP-REAL 2)|D)|K0 by JORDAN1:1;
    rng ((Sq_Circ")|K0) c= the carrier of ((TOP-REAL 2)|D)|K0
   proof let y be set;assume y in rng ((Sq_Circ")|K0);
     then consider x being set such that
     A11:x in dom ((Sq_Circ")|K0) & y=((Sq_Circ")|K0).x by FUNCT_1:def 5;
     A12:x in (dom (Sq_Circ")) /\ K0 by A11,FUNCT_1:68;
     then A13:x in K0 by XBOOLE_0:def 3;
     then reconsider p=x as Point of TOP-REAL 2 by A7;
     A14:(Sq_Circ").p=y by A11,A13,FUNCT_1:72;
     consider px being Point of TOP-REAL 2 such that A15: x=px &
         (px`2<=px`1 & -px`1<=px`2 or px`2>=px`1 & px`2<=-px`1)
         & px<>0.REAL 2 by A13;
     reconsider K00=K0 as Subset of TOP-REAL 2 by A7;
       K00=the carrier of ((TOP-REAL 2)|K00) by JORDAN1:1;
     then A16:p in the carrier of ((TOP-REAL 2)|K00) by A12,XBOOLE_0:def 3;
  for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K00 holds q`1<>0
   proof let q be Point of TOP-REAL 2;
    assume A17:q in the carrier of (TOP-REAL 2)|K00;
        the carrier of (TOP-REAL 2)|K00=K0 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A18: q=p3 & ((p3`2<=p3`1 & -p3`1<=p3`2 or p3`2>=p3`1 & p3`2<=-p3`1)
     & p3<>0.REAL 2) by A17;
       now assume A19:q`1=0;
      then q`2=0 by A18;
      hence contradiction by A18,A19,EUCLID:57,58;
     end;
    hence q`1<>0;
   end;
     then A20:p`1<>0 by A16;
     set p9=|[p`1*sqrt(1+(p`2/p`1)^2),p`2*sqrt(1+(p`2/p`1)^2)]|;
     A21:p9`1=p`1*sqrt(1+(p`2/p`1)^2) & p9`2=p`2*sqrt(1+(p`2/p`1)^2)
                                     by EUCLID:56;
        1+(p`2/p`1)^2>0 by Lm1;
      then A22:sqrt(1+(p`2/p`1)^2)>0 by SQUARE_1:93;
 A23:now assume p9=0.REAL 2;
       then 0/sqrt(1+(p`2/p`1)^2)=p`1*sqrt(1+(p`2/p`1)^2)/sqrt(1+(p`2/p`1)^2)
                                    by A21,EUCLID:56,58;
      hence contradiction by A20,A22,XCMPLX_1:90;
     end;
     A24:(Sq_Circ").p=|[p`1*sqrt(1+(p`2/p`1)^2),
     p`2*sqrt(1+(p`2/p`1)^2)]| by A15,Th38;
       p`2*sqrt(1+(p`2/p`1)^2)<=p`1*sqrt(1+(p`2/p`1)^2)
     & (-p`1)*sqrt(1+(p`2/p`1)^2)<=p`2*sqrt(1+(p`2/p`1)^2) or
     p`2*sqrt(1+(p`2/p`1)^2)>=p`1*sqrt(1+(p`2/p`1)^2) &
     p`2*sqrt(1+(p`2/p`1)^2)<=(-p`1)*sqrt(1+(p`2/p`1)^2)
                       by A15,A22,AXIOMS:25;
     then A25:p`2*sqrt(1+(p`2/p`1)^2)<=p`1*sqrt(1+(p`2/p`1)^2)
     & -(p`1*sqrt(1+(p`2/p`1)^2))<=p`2*sqrt(1+(p`2/p`1)^2) or
     p`2*sqrt(1+(p`2/p`1)^2)>=p`1*sqrt(1+(p`2/p`1)^2) &
     p`2*sqrt(1+(p`2/p`1)^2)<=-(p`1*sqrt(1+(p`2/p`1)^2)) by XCMPLX_1:175;
        p9`1=p`1*sqrt(1+(p`2/p`1)^2) & p9`2=p`2*sqrt(1+(p`2/p`1)^2)
                                 by EUCLID:56;
      then y in K0 by A14,A23,A24,A25;
    hence thesis by JORDAN1:1;
   end;
  then rng ((Sq_Circ")|K0)c= the carrier of ((TOP-REAL 2)|D) by A10,XBOOLE_1:1
;
  then (Sq_Circ")|K0 is Function of the carrier of ((TOP-REAL 2)|D)|K0,
  the carrier of ((TOP-REAL 2)|D) by A9,A10,FUNCT_2:4;
  then reconsider f=(Sq_Circ")|K0 as map of ((TOP-REAL 2)|D)|K0,
  (TOP-REAL 2)|D ;
   A26:K1 c= the carrier of TOP-REAL 2
   proof let z be set;assume z in K1;
        then consider p8 being Point of TOP-REAL 2 such that
     A27: p8=z & ((p8`1<=p8`2 & -p8`2<=p8`1 or p8`1>=p8`2 & p8`1<=-p8`2)
         & p8<>0.REAL 2);
    thus thesis by A27;
   end;
  A28:dom ((Sq_Circ")|K1)= dom ((Sq_Circ")) /\ K1 by FUNCT_1:68
       .=((the carrier of TOP-REAL 2)) /\ K1 by Th39,FUNCT_2:def 1
       .=K1 by A26,XBOOLE_1:28;
  A29: K1=the carrier of ((TOP-REAL 2)|D)|K1 by JORDAN1:1;
    rng ((Sq_Circ")|K1) c= the carrier of ((TOP-REAL 2)|D)|K1
   proof let y be set;assume y in rng ((Sq_Circ")|K1);
     then consider x being set such that
     A30:x in dom ((Sq_Circ")|K1) & y=((Sq_Circ")|K1).x by FUNCT_1:def 5;
     A31:x in (dom (Sq_Circ")) /\ K1 by A30,FUNCT_1:68;
     then A32:x in K1 by XBOOLE_0:def 3;
     then reconsider p=x as Point of TOP-REAL 2 by A26;
     A33:(Sq_Circ").p=y by A30,A32,FUNCT_1:72;
     consider px being Point of TOP-REAL 2 such that A34: x=px &
         (px`1<=px`2 & -px`2<=px`1 or px`1>=px`2 & px`1<=-px`2)
         & px<>0.REAL 2 by A32;
     reconsider K10=K1 as Subset of TOP-REAL 2 by A26;
       K10=the carrier of ((TOP-REAL 2)|K10) by JORDAN1:1;
     then A35:p in the carrier of ((TOP-REAL 2)|K10) by A31,XBOOLE_0:def 3;
  for q being Point of TOP-REAL 2 st q in
  the carrier of (TOP-REAL 2)|K10 holds q`2<>0
   proof let q be Point of TOP-REAL 2;
    assume A36:q in the carrier of (TOP-REAL 2)|K10;
        the carrier of (TOP-REAL 2)|K10=K1 by JORDAN1:1;
     then consider p3 being Point of TOP-REAL 2 such that
     A37: q=p3 & ((p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3`2)
     & p3<>0.REAL 2) by A36;
       now assume A38:q`2=0;
        then q`1=0 by A37;
      hence contradiction by A37,A38,EUCLID:57,58;
     end;
    hence q`2<>0;
   end;
     then A39:p`2<>0 by A35;
     set p9=|[p`1*sqrt(1+(p`1/p`2)^2),p`2*sqrt(1+(p`1/p`2)^2)]|;
     A40:p9`1=p`1*sqrt(1+(p`1/p`2)^2) & p9`2=p`2*sqrt(1+(p`1/p`2)^2)
                                     by EUCLID:56;
        1+(p`1/p`2)^2>0 by Lm1;
      then A41:sqrt(1+(p`1/p`2)^2)>0 by SQUARE_1:93;
     A42:now assume p9=0.REAL 2;
       then 0/sqrt(1+(p`1/p`2)^2)=p`2*sqrt(1+(p`1/p`2)^2)/sqrt(1+(p`1/p`2)^2)
                                    by A40,EUCLID:56,58;
      hence contradiction by A39,A41,XCMPLX_1:90;
     end;
     A43:(Sq_Circ").p=|[p`1*sqrt(1+(p`1/p`2)^2),
        p`2*sqrt(1+(p`1/p`2)^2)]| by A34,Th40;
       p`1*sqrt(1+(p`1/p`2)^2)<=p`2*sqrt(1+(p`1/p`2)^2)
     & (-p`2)*sqrt(1+(p`1/p`2)^2)<=p`1*sqrt(1+(p`1/p`2)^2) or
     p`1*sqrt(1+(p`1/p`2)^2)>=p`2*sqrt(1+(p`1/p`2)^2) &
     p`1*sqrt(1+(p`1/p`2)^2)<=(-p`2)*sqrt(1+(p`1/p`2)^2)
                       by A34,A41,AXIOMS:25;
     then A44:p`1*sqrt(1+(p`1/p`2)^2)<=p`2*sqrt(1+(p`1/p`2)^2)
     & -(p`2*sqrt(1+(p`1/p`2)^2))<=p`1*sqrt(1+(p`1/p`2)^2) or
     p`1*sqrt(1+(p`1/p`2)^2)>=p`2*sqrt(1+(p`1/p`2)^2) &
     p`1*sqrt(1+(p`1/p`2)^2)<=-(p`2*sqrt(1+(p`1/p`2)^2)) by XCMPLX_1:175;
        p9`2=p`2*sqrt(1+(p`1/p`2)^2) & p9`1=p`1*sqrt(1+(p`1/p`2)^2)
                                 by EUCLID:56;
      then y in K1 by A33,A42,A43,A44;
    hence y in the carrier of ((TOP-REAL 2)|D)|K1 by JORDAN1:1;
   end;
  then rng ((Sq_Circ")|K1)c= the carrier of ((TOP-REAL 2)|D) by A29,XBOOLE_1:1
;
  then (Sq_Circ")|K1 is Function of the carrier of ((TOP-REAL 2)|D)|K1,
  the carrier of ((TOP-REAL 2)|D) by A28,A29,FUNCT_2:4;
  then reconsider g=(Sq_Circ")|K1 as map of ((TOP-REAL 2)|D)|K1,
  ((TOP-REAL 2)|D) ;
  A45:K0=[#](((TOP-REAL 2)|D)|K0) by PRE_TOPC:def 10;
  A46:K1=[#](((TOP-REAL 2)|D)|K1) by PRE_TOPC:def 10;
  A47:D= [#]((TOP-REAL 2)|D) by PRE_TOPC:def 10;
  A48:K0 \/ K1 c= D
   proof let x be set;assume A49: x in K0 \/ K1;
       now per cases by A49,XBOOLE_0:def 2;
     case x in K0;
       then consider p such that A50:p=x &
       (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1)
         & p<>0.REAL 2;
     thus x in the carrier of TOP-REAL 2 & not x=0.REAL 2 by A50;
     case x in K1;
       then consider p such that A51:p=x &
       (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)
         & p<>0.REAL 2;
     thus x in the carrier of TOP-REAL 2 & x<>0.REAL 2 by A51;
     end;
     then x in the carrier of TOP-REAL 2 & not x in {0.REAL 2} by TARSKI:def 1
;
    hence x in D by A2,XBOOLE_0:def 4;
   end;
    D c= K0 \/ K1
   proof let x be set;assume A52: x in D;
     then A53:x in the carrier of TOP-REAL 2 & not x in {0.REAL 2}
                                     by A2,XBOOLE_0:def 4;
     reconsider px=x as Point of TOP-REAL 2 by A52;
       (px`2<=px`1 & -px`1<=px`2 or px`2>=px`1 & px`2<=-px`1)
         & px<>0.REAL 2 or
       (px`1<=px`2 & -px`2<=px`1 or px`1>=px`2 & px`1<=-px`2)
         & px<>0.REAL 2 by A53,REAL_2:110,TARSKI:def 1;
     then x in K0 or x in K1;
    hence x in K0 \/ K1 by XBOOLE_0:def 2;
   end;
  then A54:([#](((TOP-REAL 2)|D)|K0)) \/ [#](((TOP-REAL 2)|D)|K1)
  = [#]((TOP-REAL 2)|D) by A45,A46,A47,A48,XBOOLE_0:def 10;
    f=(Sq_Circ")|K0 & D=(the carrier of TOP-REAL 2) \ {0.REAL 2}
  & K0={p:(p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) & p<>0.REAL 2}
                   by A2;
  then A55: f is continuous & K0 is closed by Th49;
    g=(Sq_Circ")|K1 & D=(the carrier of TOP-REAL 2) \ {0.REAL 2}
  & K1={p:(p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2) & p<>0.REAL 2}
                   by A2;
  then A56: g is continuous & K1 is closed by Th50;
  A57: now let x be set;assume x in ([#]((((TOP-REAL 2)|D)|K0)))
        /\ ([#] ((((TOP-REAL 2)|D)|K1)));
     then A58:x in K0 & x in K1 by A45,A46,XBOOLE_0:def 3;
     then f.x=(Sq_Circ").x by FUNCT_1:72;
    hence f.x = g.x by A58,FUNCT_1:72;
   end;
  then consider h being map of (TOP-REAL 2)|D,(TOP-REAL 2)|D
  such that A59: h= f+*g & h is continuous
                          by A45,A46,A54,A55,A56,JGRAPH_2:9;
  A60:dom h=the carrier of ((TOP-REAL 2)|D) by FUNCT_2:def 1;
  A61:the carrier of ((TOP-REAL 2)|D) = D by JORDAN1:1;
  A62:the carrier of ((TOP-REAL 2)|D)=[#](((TOP-REAL 2)|D)) by PRE_TOPC:12
       .=((the carrier of TOP-REAL 2)\ {0.REAL 2}) by A2,PRE_TOPC:def 10;
    dom (Sq_Circ")=(the carrier of (TOP-REAL 2)) by Th39,FUNCT_2:def 1;
  then A63:dom ((Sq_Circ")|D)=(the carrier of (TOP-REAL 2))/\ D by FUNCT_1:68
              .=the carrier of ((TOP-REAL 2)|D) by A61,XBOOLE_1:28;
  A64:dom f=K0 by A10,FUNCT_2:def 1;
  A65:K0=[#](((TOP-REAL 2)|D)|K0) by PRE_TOPC:def 10;
  A66:dom g=K1 by A29,FUNCT_2:def 1;
   K1=[#](((TOP-REAL 2)|D)|K1) by PRE_TOPC:def 10;
  then A67:f tolerates g by A57,A64,A65,A66,PARTFUN1:def 6;
    for x being set st x in dom h holds h.x=((Sq_Circ")|D).x
   proof let x be set;assume A68: x in dom h;
     then x in (the carrier of TOP-REAL 2) & not x in {0.REAL 2}
                     by A62,XBOOLE_0:def 4;
     then A69:x <>0.REAL 2 by TARSKI:def 1;
     reconsider p=x as Point of TOP-REAL 2 by A62,A68,XBOOLE_0:def 4;
       x in (the carrier of TOP-REAL 2)\D` by A1,A62,A68;
then A70:   x in D`` by SUBSET_1:def 5;
     per cases;
     suppose A71:x in K0;
    A72:(Sq_Circ")|D.p=(Sq_Circ").p by A70,FUNCT_1:72.=f.p by A71,FUNCT_1:72;
         h.p=(g+*f).p by A59,A67,FUNCT_4:35
       .=f.p by A64,A71,FUNCT_4:14;
      hence h.x=(Sq_Circ")|D.x by A72;
     suppose not x in K0;
       then not (p`2<=p`1 & -p`1<=p`2 or p`2>=p`1 & p`2<=-p`1) by A69;
       then (p`1<=p`2 & -p`2<=p`1 or p`1>=p`2 & p`1<=-p`2)by REAL_2:110;
       then A73:x in K1 by A69;
         (Sq_Circ")|D.p=(Sq_Circ").p by A70,FUNCT_1:72.=g.p
                           by A73,FUNCT_1:72;
      hence h.x=(Sq_Circ")|D.x by A59,A66,A73,FUNCT_4:14;
   end;
  then f+*g=(Sq_Circ")|D by A59,A60,A63,FUNCT_1:9;
 hence thesis by A45,A46,A54,A55,A56,A57,JGRAPH_2:9;
end;

theorem Th52:
ex h being map of TOP-REAL 2,TOP-REAL 2 st h=Sq_Circ" & h is continuous
proof
 reconsider f=(Sq_Circ") as map of (TOP-REAL 2),(TOP-REAL 2) by Th39;
  (the carrier of TOP-REAL 2) \{0.REAL 2} c=(the carrier of TOP-REAL 2)
                         by XBOOLE_1:36;
 then reconsider D=(the carrier of TOP-REAL 2) \{0.REAL 2}
   as non empty Subset of TOP-REAL 2 by JGRAPH_2:19;
 A1: f.(0.REAL 2)=0.REAL 2 by Th38;
 A2: D`= {0.REAL 2} by Th30;
 A3: for p being Point of (TOP-REAL 2)|D holds f.p<>f.(0.REAL 2)
  proof let p be Point of (TOP-REAL 2)|D;
    A4:the carrier of (TOP-REAL 2)|D=[#]((TOP-REAL 2)|D) by PRE_TOPC:12;
    A5: [#]((TOP-REAL 2)|D)=D by PRE_TOPC:def 10;
    then A6:p in the carrier of TOP-REAL 2 & not p in {0.REAL 2}
                         by A4,XBOOLE_0:def 4;
    reconsider q=p as Point of TOP-REAL 2 by A4,A5,XBOOLE_0:def 4;
    A7:not p=0.REAL 2 by A6,TARSKI:def 1;
    per cases;
    suppose A8:not(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
      then A9:q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 & q`1<=-q`2 by JGRAPH_2:23;
      A10:now assume A11:q`2=0;
        then q`1=0 by A9;
       hence contradiction by A7,A11,EUCLID:57,58;
      end;
      set q9=|[q`1*sqrt(1+(q`1/q`2)^2),q`2*sqrt(1+(q`1/q`2)^2)]|;
      A12:q9`1=q`1*sqrt(1+(q`1/q`2)^2) & q9`2=q`2*sqrt(1+(q`1/q`2)^2)
                                  by EUCLID:56;
        1+(q`1/q`2)^2>0 by Lm1;
      then A13:sqrt(1+(q`1/q`2)^2)>0 by SQUARE_1:93;
        now assume q9=0.REAL 2;
       then 0 *q`2=q`2*sqrt(1+(q`1/q`2)^2) by A12,EUCLID:56,58;
       then 0 *sqrt(1+(q`1/q`2)^2)=q`2*sqrt(1+(q`1/q`2)^2)/sqrt(1+(q`1/q`2)^2)
;
      hence contradiction by A10,A13,XCMPLX_1:90;
     end;
     hence thesis by A1,A7,A8,Th38;
    suppose A14:(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
      A15:now assume A16:q`1=0;
        then q`2=0 by A14;
       hence contradiction by A7,A16,EUCLID:57,58;
      end;
      set q9=|[q`1*sqrt(1+(q`2/q`1)^2),q`2*sqrt(1+(q`2/q`1)^2)]|;
      A17:q9`1=q`1*sqrt(1+(q`2/q`1)^2) & q9`2=q`2*sqrt(1+(q`2/q`1)^2)
                                  by EUCLID:56;
        1+(q`2/q`1)^2>0 by Lm1;
      then A18:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
        now assume q9=0.REAL 2;
       then 0/sqrt(1+(q`2/q`1)^2)=q`1*sqrt(1+(q`2/q`1)^2)/sqrt(1+(q`2/q`1)^2)
                                by A17,EUCLID:56,58;
      hence contradiction by A15,A18,XCMPLX_1:90;
     end;
     hence thesis by A1,A7,A14,Th38;
  end;
 A19:ex h being map of (TOP-REAL 2)|D,(TOP-REAL 2)|D
  st h=(Sq_Circ")|D & h is continuous by A2,Th51;
   for V being Subset of TOP-REAL 2 st f.(0.REAL 2) in V & V is open
 ex W being Subset of TOP-REAL 2 st 0.REAL 2 in W
 & W is open & f.:W c= V
  proof let V be Subset of TOP-REAL 2;
    assume A20:f.(0.REAL 2) in V & V is open;
     A21:the carrier of TOP-REAL 2=REAL 2 by EUCLID:25;
A22:  Euclid 2=MetrStruct(#REAL 2,Pitag_dist 2#) by EUCLID:def 7;
     then reconsider u0=0.REAL 2 as Point of Euclid 2 by EUCLID:25;
     consider r being real number such that A23:r>0 & Ball(u0,r) c= V
       by A1,A20,Lm2,TOPMETR:22;
     reconsider r as Real by XREAL_0:def 1;
       sqrt(2)>0 by SQUARE_1:93;
     then A24: r/sqrt(2)>0 by A23,REAL_2:127;
     reconsider W1=Ball(u0,r), V1=Ball(u0,r/sqrt(2)) as Subset of TOP-REAL 2
                       by A21,A22;
     A25:u0 in V1 by A24,GOBOARD6:4;
     A26:V1 is open by GOBOARD6:6;
       f.:V1 c= W1
      proof let z be set;assume z in f.:V1;
        then consider y being set such that
        A27: y in dom f & y in V1 & z=f.y by FUNCT_1:def 12;
        reconsider q=y as Point of TOP-REAL 2 by A27;
        reconsider qy=q as Point of Euclid 2 by A22,EUCLID:25;
          z in rng f by A27,FUNCT_1:def 5;
        then reconsider qz=z as Point of TOP-REAL 2;
        reconsider pz=qz as Point of Euclid 2 by A22,EUCLID:25;
          dist(u0,qy)<r/sqrt(2) by A27,METRIC_1:12;
        then |.(0.REAL 2) - q.|<r/sqrt(2) by JGRAPH_1:45;
        then sqrt((((0.REAL 2) - q)`1)^2+(((0.REAL 2) - q)`2)^2)
                                < r/sqrt(2) by JGRAPH_1:47;
        then sqrt(((0.REAL 2)`1 - q`1)^2+(((0.REAL 2) - q)`2)^2)<r/sqrt(2)
                                  by TOPREAL3:8;
        then sqrt(((0.REAL 2)`1 - q`1)^2+((0.REAL 2)`2 - q`2)^2)<r/sqrt(2)
                                  by TOPREAL3:8;
        then sqrt((- q`1)^2+(0 - q`2)^2)<r/sqrt(2) by JGRAPH_2:11,XCMPLX_1:150
;
        then sqrt((- q`1)^2+(- q`2)^2)<r/sqrt(2) by XCMPLX_1:150;
        then sqrt((q`1)^2+(- q`2)^2)<r/sqrt(2) by SQUARE_1:61;
        then A28:sqrt((q`1)^2+(q`2)^2)<r/sqrt(2) by SQUARE_1:61;
        A29:(q`1)^2 >=0 by SQUARE_1:72;
        A30:(q`2)^2>=0 by SQUARE_1:72;
        then A31:(q`1)^2+(q`2)^2 >=0+0 by A29,REAL_1:55;
        A32:sqrt(2)>0 by SQUARE_1:93;
        then sqrt((q`1)^2+(q`2)^2)*sqrt(2)< r/sqrt(2)*sqrt(2) by A28,REAL_1:70
;
        then sqrt(((q`1)^2+(q`2)^2)*2)< r/sqrt(2)*sqrt(2) by A31,SQUARE_1:97;
        then A33:sqrt(((q`1)^2+(q`2)^2)*2)< r by A32,XCMPLX_1:88;
        per cases;
        suppose q=0.REAL 2; then z=0.REAL 2 by A27,Th38;
         hence thesis by A23,GOBOARD6:4;
        suppose A34:q<>0.REAL 2 &
          (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          then A35:(Sq_Circ").q=|[q`1*sqrt(1+(q`2/q`1)^2),q`2*sqrt(1+(q`2/q`1)
^2)]|
                                 by Th38;
          A36:((0.REAL 2) - qz)`1=(0.REAL 2)`1-qz`1 by TOPREAL3:8
                      .= -qz`1 by JGRAPH_2:11,XCMPLX_1:150;
          A37:((0.REAL 2) - qz)`2=(0.REAL 2)`2-qz`2 by TOPREAL3:8
                      .= -qz`2 by JGRAPH_2:11,XCMPLX_1:150;
          A38:qz`1=q`1*sqrt(1+(q`2/q`1)^2) & qz`2=q`2*sqrt(1+(q`2/q`1)^2)
                                 by A27,A35,EUCLID:56;
          A39:now per cases by A34;
          case A40:q`2<=q`1 & -q`1<=q`2;
              now per cases;
            case 0<=q`2;
             hence (q`2)^2<=(q`1)^2 by A40,SQUARE_1:77;
            case A41:0>q`2;
A42:           --q`1>=-q`2 by A40,REAL_1:50;
                -0<-q`2 by A41,REAL_1:50;
              then (-q`2)^2<=(q`1)^2 by A42,SQUARE_1:77;
             hence (q`2)^2<=(q`1)^2 by SQUARE_1:61;
            end;
           hence (q`2)^2<=(q`1)^2;
          case A43: q`2>=q`1 & q`2<=-q`1;
              now per cases;
            case 0>=q`2;
              then A44: -q`2>= -0 by REAL_1:50;
                -q`2<=-q`1 by A43,REAL_1:50;
              then (-q`2)^2<=(-q`1)^2 by A44,SQUARE_1:77;
              then (q`2)^2<=(-q`1)^2 by SQUARE_1:61;
             hence (q`2)^2<=(q`1)^2 by SQUARE_1:61;
            case 0<q`2;
              then (q`2)^2<=(-q`1)^2 by A43,SQUARE_1:77;
             hence (q`2)^2<=(q`1)^2 by SQUARE_1:61;
            end;
           hence (q`2)^2<=(q`1)^2;
          end;
          A45:now assume (q`1)^2<=0;
            then (q`1)^2=0 by SQUARE_1:72;
            then A46:q`1=0 by SQUARE_1:73;
            then q`2=0 by A34;
           hence contradiction by A34,A46,EUCLID:57,58;
          end;
          then (q`2)^2/(q`1)^2<=(q`1)^2/(q`1)^2 by A39,REAL_1:73;
          then (q`2/q`1)^2<=(q`1)^2/(q`1)^2 by SQUARE_1:69;
          then (q`2/q`1)^2 <=1 by A45,XCMPLX_1:60;
          then A47:1+(q`2/q`1)^2<=1+1 by REAL_1:55;
          then A48:(q`1)^2*(1+(q`2/q`1)^2)<=(q`1)^2*2 by A29,AXIOMS:25;
          A49:(q`2)^2*(1+(q`2/q`1)^2)<=(q`2)^2*2 by A30,A47,AXIOMS:25;
          A50:1+(q`2/q`1)^2>0 by Lm1;
           (qz`1)^2=(q`1)^2*(sqrt(1+(q`2/q`1)^2))^2 by A38,SQUARE_1:68;
          then A51:(qz`1)^2<=(q`1)^2*2 by A48,A50,SQUARE_1:def 4;
          A52:(qz`1)^2>=0 by SQUARE_1:72;
          A53:(qz`2)^2=(q`2)^2*(sqrt(1+(q`2/q`1)^2))^2 by A38,SQUARE_1:68;
          A54:(qz`2)^2>=0 by SQUARE_1:72;
          A55:(qz`2)^2<=(q`2)^2*2 by A49,A50,A53,SQUARE_1:def 4;
          A56:sqrt((((0.REAL 2) - qz)`1)^2+(((0.REAL 2) - qz)`2)^2)
          =sqrt((qz`1)^2+(-qz`2)^2) by A36,A37,SQUARE_1:61
          .=sqrt((qz`1)^2+(qz`2)^2) by SQUARE_1:61;
          A57:(qz`1)^2+(qz`2)^2<=(q`1)^2*2+(q`2)^2*2 by A51,A55,REAL_1:55;
            0+0<= (qz`1)^2+(qz`2)^2 by A52,A54,REAL_1:55;
          then sqrt((qz`1)^2+(qz`2)^2) <= sqrt((q`1)^2*2+(q`2)^2*2)
                          by A57,SQUARE_1:94;
          then sqrt((qz`1)^2+(qz`2)^2) <= sqrt(((q`1)^2+(q`2)^2)*2)
                          by XCMPLX_1:8;
          then sqrt((((0.REAL 2) - qz)`1)^2+(((0.REAL 2) - qz)`2)^2)<r
                           by A33,A56,AXIOMS:22;
          then |.(0.REAL 2) - qz.|<r by JGRAPH_1:47;
          then dist(u0,pz)<r by JGRAPH_1:45;
          hence thesis by METRIC_1:12;
        suppose A58:q<>0.REAL 2 &
         not (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          then A59:(Sq_Circ").q=|[q`1*sqrt(1+(q`1/q`2)^2),q`2*sqrt(1+(q`1/q`2)
^2)]|
                        by Th38;
          A60:((0.REAL 2) - qz)`1=(0.REAL 2)`1-qz`1 by TOPREAL3:8
                      .= -qz`1 by JGRAPH_2:11,XCMPLX_1:150;
          A61:((0.REAL 2) - qz)`2=(0.REAL 2)`2-qz`2 by TOPREAL3:8
                      .= -qz`2 by JGRAPH_2:11,XCMPLX_1:150;
          A62:qz`1=q`1*sqrt(1+(q`1/q`2)^2) & qz`2=q`2*sqrt(1+(q`1/q`2)^2)
                                 by A27,A59,EUCLID:56;
          A63: q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 & q`1<=-q`2 by A58,JGRAPH_2:23;
          A64:now per cases by A58,JGRAPH_2:23;
          case A65:q`1<=q`2 & -q`2<=q`1;
              now per cases;
            case 0<=q`1;
             hence (q`1)^2<=(q`2)^2 by A65,SQUARE_1:77;
            case A66:0>q`1;
              A67: --q`2>=-q`1 by A65,REAL_1:50;
                -0<-q`1 by A66,REAL_1:50;
              then (-q`1)^2<=(q`2)^2 by A67,SQUARE_1:77;
             hence (q`1)^2<=(q`2)^2 by SQUARE_1:61;
            end;
           hence (q`1)^2<=(q`2)^2;
          case A68: q`1>=q`2 & q`1<=-q`2;
              now per cases;
            case 0>=q`1;
              then A69: -q`1>= -0 by REAL_1:50;
                -q`1<=-q`2 by A68,REAL_1:50;
              then (-q`1)^2<=(-q`2)^2 by A69,SQUARE_1:77;
              then (q`1)^2<=(-q`2)^2 by SQUARE_1:61;
             hence (q`1)^2<=(q`2)^2 by SQUARE_1:61;
            case 0<q`1;
              then (q`1)^2<=(-q`2)^2 by A68,SQUARE_1:77;
             hence (q`1)^2<=(q`2)^2 by SQUARE_1:61;
            end;
           hence (q`1)^2<=(q`2)^2;
          end;
          A70:now assume (q`2)^2<=0;
            then (q`2)^2=0 by SQUARE_1:72;
            then q`2=0 by SQUARE_1:73;
           hence contradiction by A58,A63;
          end;
          then (q`1)^2/(q`2)^2<=(q`2)^2/(q`2)^2 by A64,REAL_1:73;
          then (q`1/q`2)^2<=(q`2)^2/(q`2)^2 by SQUARE_1:69;
          then (q`1/q`2)^2 <=1 by A70,XCMPLX_1:60;
          then A71:1+(q`1/q`2)^2<=1+1 by REAL_1:55;
          then A72:(q`2)^2*(1+(q`1/q`2)^2)<=(q`2)^2*2 by A30,AXIOMS:25;
          A73:(q`1)^2*(1+(q`1/q`2)^2)<=(q`1)^2*2 by A29,A71,AXIOMS:25;
           1+(q`1/q`2)^2>0 by Lm1;
          then A74:(sqrt(1+(q`1/q`2)^2))^2=1+(q`1/q`2)^2 by SQUARE_1:def 4;
          then A75:(qz`2)^2<=(q`2)^2*2 by A62,A72,SQUARE_1:68;
          A76:(qz`2)^2>=0 by SQUARE_1:72;
          A77:(qz`1)^2>=0 by SQUARE_1:72;
          A78:(qz`1)^2<=(q`1)^2*2 by A62,A73,A74,SQUARE_1:68;
          A79:sqrt((((0.REAL 2) - qz)`2)^2+(((0.REAL 2) - qz)`1)^2)
           =sqrt((qz`2)^2+(-qz`1)^2) by A60,A61,SQUARE_1:61
          .=sqrt((qz`2)^2+(qz`1)^2) by SQUARE_1:61;
          A80:(qz`2)^2+(qz`1)^2<=(q`2)^2*2+(q`1)^2*2 by A75,A78,REAL_1:55;
            0+0<= (qz`2)^2+(qz`1)^2 by A76,A77,REAL_1:55;
          then sqrt((qz`2)^2+(qz`1)^2) <= sqrt((q`2)^2*2+(q`1)^2*2)
                          by A80,SQUARE_1:94;
          then sqrt((qz`2)^2+(qz`1)^2) <= sqrt(((q`2)^2+(q`1)^2)*2)
                          by XCMPLX_1:8;
          then sqrt((((0.REAL 2) - qz)`2)^2+(((0.REAL 2) - qz)`1)^2)<r
                           by A33,A79,AXIOMS:22;
          then |.(0.REAL 2) - qz.|<r by JGRAPH_1:47;
          then dist(u0,pz)<r by JGRAPH_1:45;
         hence thesis by METRIC_1:12;
      end;
     then f.:V1 c= V by A23,XBOOLE_1:1;
   hence ex W being Subset of TOP-REAL 2 st 0.REAL 2 in W
       & W is open & f.:W c= V by A25,A26;
  end;
  then f is continuous by A1,A2,A3,A19,Th13;
 hence thesis;
end;

Lm15: Sq_Circ" is one-to-one by FUNCT_1:62;

canceled;

theorem Th54: Sq_Circ is map of TOP-REAL 2,TOP-REAL 2 &
 rng Sq_Circ = the carrier of TOP-REAL 2 &
 for f being map of TOP-REAL 2,TOP-REAL 2 st f=Sq_Circ holds
   f is_homeomorphism
proof thus Sq_Circ is map of TOP-REAL 2,TOP-REAL 2 ;
  A1:for f being map of TOP-REAL 2,TOP-REAL 2 st f=Sq_Circ holds
    rng Sq_Circ=the carrier of TOP-REAL 2 & f is_homeomorphism
  proof let f be map of TOP-REAL 2,TOP-REAL 2;
    assume A2:f=Sq_Circ;
    A3:dom f=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
    then A4:dom f=[#](TOP-REAL 2) by PRE_TOPC:12;
    consider h being map of (TOP-REAL 2),(TOP-REAL 2) such that
    A5: h=Sq_Circ & h is continuous by Th31;
    consider h2 being map of (TOP-REAL 2),(TOP-REAL 2) such that
    A6: h2=Sq_Circ" & h2 is continuous by Th52;
    A7: the carrier of TOP-REAL 2 c= rng f
    proof let y be set;assume y in the carrier of TOP-REAL 2;
     then reconsider p2=y as Point of TOP-REAL 2;
     set q=p2;
       now per cases;
     case q=0.REAL 2;
       then q in dom Sq_Circ & y=Sq_Circ.q by A2,A3,Def1;
      hence ex x being set st x in dom Sq_Circ & y=Sq_Circ.x;
     case A8:q<>0.REAL 2 &
          (q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          set px=|[q`1*sqrt(1+(q`2/q`1)^2),q`2*sqrt(1+(q`2/q`1)^2)]|;
        A9: px`1 = q`1*sqrt(1+(q`2/q`1)^2) &
         px`2 = q`2*sqrt(1+(q`2/q`1)^2) by EUCLID:56;
          1+(q`2/q`1)^2>0 by Lm1;
        then A10:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
        then A11:px`2/px`1=q`2/q`1 by A9,XCMPLX_1:92;
        A12: now assume px`1=0 & px`2=0;
          then A13:q`1*sqrt(1+(q`2/q`1)^2)=0 & q`2*sqrt(1+(q`2/q`1)^2)=0
            by EUCLID:56;
          then A14:q`1=0 by A10,XCMPLX_1:6;
            q`2=0 by A10,A13,XCMPLX_1:6;
         hence contradiction by A8,A14,EUCLID:57,58;
        end;
          q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 &
        q`2*sqrt(1+(q`2/q`1)^2) <= (-q`1)*sqrt(1+(q`2/q`1)^2)
                             by A8,A10,AXIOMS:25;
        then q`2<=q`1 & (-q`1)*sqrt(1+(q`2/q`1)^2) <= q`2*sqrt(1+(q`2/q`1)^2)
           or px`2>=px`1 & px`2<=-px`1 by A9,A10,AXIOMS:25,XCMPLX_1:175;
        then q`2*sqrt(1+(q`2/q`1)^2) <= q`1*sqrt(1+(q`2/q`1)^2) & -px`1<=px`2
           or px`2>=px`1 & px`2<=-px`1 by A9,A10,AXIOMS:25,XCMPLX_1:175;
    then A15:Sq_Circ.px=|[px`1/sqrt(1+(px`2/px`1)^2),px`2/sqrt(1+(px`2/px`1)^2)
]|
                                 by A9,A12,Def1,JGRAPH_2:11;
        A16:px`1/sqrt(1+(px`2/px`1)^2)=q`1 by A9,A10,A11,XCMPLX_1:90;
         px`2/sqrt(1+(px`2/px`1)^2)=q`2 by A9,A10,A11,XCMPLX_1:90;
        then A17:q=Sq_Circ.px by A15,A16,EUCLID:57;
          dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
      hence ex x being set st x in dom Sq_Circ & y=Sq_Circ.x by A17;
     case A18:q<>0.REAL 2 & not(q`2<=q`1 & -q`1<=q`2 or q`2>=q`1 & q`2<=-q`1);
          set px=|[q`1*sqrt(1+(q`1/q`2)^2),q`2*sqrt(1+(q`1/q`2)^2)]|;
        A19:q<>0.REAL 2 & (q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 & q`1<=-q`2)
                          by A18,JGRAPH_2:23;
        A20: px`2 = q`2*sqrt(1+(q`1/q`2)^2) &
         px`1 = q`1*sqrt(1+(q`1/q`2)^2) by EUCLID:56;
          1+(q`1/q`2)^2>0 by Lm1;
        then A21:sqrt(1+(q`1/q`2)^2)>0 by SQUARE_1:93;
        then A22:px`1/px`2=q`1/q`2 by A20,XCMPLX_1:92;
        A23: now assume px`2=0 & px`1=0;
          then A24:q`2*sqrt(1+(q`1/q`2)^2)=0 & q`1*sqrt(1+(q`1/q`2)^2)=0
            by EUCLID:56;
          then q`2=0 by A21,XCMPLX_1:6;
         hence contradiction by A18,A21,A24,XCMPLX_1:6;
        end;
          q`1<=q`2 & -q`2<=q`1 or q`1>=q`2 &
        q`1*sqrt(1+(q`1/q`2)^2) <= (-q`2)*sqrt(1+(q`1/q`2)^2)
                             by A19,A21,AXIOMS:25;
        then q`1<=q`2 & (-q`2)*sqrt(1+(q`1/q`2)^2) <= q`1*sqrt(1+(q`1/q`2)^2)
           or px`1>=px`2 & px`1<=-px`2 by A20,A21,AXIOMS:25,XCMPLX_1:175;
        then q`1*sqrt(1+(q`1/q`2)^2) <= q`2*sqrt(1+(q`1/q`2)^2) & -px`2<=px`1
           or px`1>=px`2 & px`1<=-px`2 by A20,A21,AXIOMS:25,XCMPLX_1:175;
     then A25:Sq_Circ.px=|[px`1/sqrt(1+(px`1/px`2)^2),px`2/sqrt(1+(px`1/px`2)^2
)]|
                                 by A20,A23,Th14,JGRAPH_2:11;
        A26:px`2/sqrt(1+(px`1/px`2)^2)=q`2 by A20,A21,A22,XCMPLX_1:90;
         px`1/sqrt(1+(px`1/px`2)^2)=q`1 by A20,A21,A22,XCMPLX_1:90;
        then A27:q=Sq_Circ.px by A25,A26,EUCLID:57;
          dom Sq_Circ=the carrier of TOP-REAL 2 by FUNCT_2:def 1;
      hence ex x being set st x in dom Sq_Circ & y=Sq_Circ.x by A27;
     end;
    hence y in rng f by A2,FUNCT_1:def 5;
   end;
   then rng f=the carrier of TOP-REAL 2 by XBOOLE_0:def 10;
   then A28:rng f=[#](TOP-REAL 2) by PRE_TOPC:12;
   A29:rng f=dom ((f qua Function)") by A2,FUNCT_1:55
      .=dom (f/") by A2,A28,TOPS_2:def 4
      .=the carrier of TOP-REAL 2 by FUNCT_2:def 1
      .=[#](TOP-REAL 2) by PRE_TOPC:12;
    reconsider g=f/" as map of TOP-REAL 2,TOP-REAL 2;
      g=Sq_Circ" by A2,A29,TOPS_2:def 4;
   hence rng Sq_Circ=the carrier of TOP-REAL 2 &
   f is_homeomorphism by A2,A4,A5,A6,A7,A29,TOPS_2:def 5,XBOOLE_0:def 10;
  end;
 thus rng Sq_Circ=the carrier of TOP-REAL 2 by A1;
 thus thesis by A1;
end;

Lm16:now let pz2, pz1 be real number;
  assume ((pz2)^2+(pz1)^2-1)*(pz2)^2<=(pz1)^2;
  then ((pz2)^2+((pz1)^2-1))*(pz2)^2<=(pz1)^2 by XCMPLX_1:29;
  then (pz2)^2*(pz2)^2+((pz1)^2-1)*(pz2)^2<=(pz1)^2 by XCMPLX_1:8;
  then (pz2)^2*(pz2)^2+(pz2)^2*((pz1)^2-1)-(pz1)^2
                   <=(pz1)^2-(pz1)^2 by REAL_1:49;
  then (pz2)^2*(pz2)^2+(pz2)^2*((pz1)^2-1)-(pz1)^2<=0 by XCMPLX_1:14;
  then (pz2)^2*(pz2)^2+((pz2)^2*(pz1)^2-(pz2)^2*1)-(pz1)^2<=0 by XCMPLX_1:40;
  then (pz2)^2*(pz2)^2+(pz2)^2*(pz1)^2-(pz2)^2*1-(pz1)^2<=0 by XCMPLX_1:29;
  then (pz2)^2*(pz2)^2-(pz2)^2*1+(pz2)^2*(pz1)^2-1 *(pz1)^2<=0 by XCMPLX_1:29
;
  then (pz2)^2*((pz2)^2-1)+(pz2)^2*(pz1)^2-1 *(pz1)^2<=0 by XCMPLX_1:40;
  then (pz2)^2*((pz2)^2-1)+((pz2)^2*(pz1)^2-1 *(pz1)^2)<=0
                            by XCMPLX_1:29;
  then (pz2)^2*((pz2)^2-1)+((pz2)^2-1)*(pz1)^2<=0 by XCMPLX_1:40;
  hence ((pz2)^2-1)*((pz2)^2+(pz1)^2)<=0 by XCMPLX_1:8;
end;

Lm17:now let pu2, pu1 be real number;
 assume ((pu2)^2+(pu1)^2-1)*(pu2)^2=(pu1)^2;
  then ((pu2)^2+((pu1)^2-1))*(pu2)^2=(pu1)^2 by XCMPLX_1:29;
  then (pu2)^2*(pu2)^2+((pu1)^2-1)*(pu2)^2=(pu1)^2 by XCMPLX_1:8;
  hence 0=(pu2)^2*(pu2)^2+(pu2)^2*((pu1)^2-1)-(pu1)^2 by XCMPLX_1:14
  .= (pu2)^2*(pu2)^2+((pu2)^2*(pu1)^2-(pu2)^2*1)-(pu1)^2 by XCMPLX_1:40
  .= (pu2)^2*(pu2)^2+(pu2)^2*(pu1)^2-(pu2)^2*1-(pu1)^2 by XCMPLX_1:29
  .= (pu2)^2*(pu2)^2-(pu2)^2*1+(pu2)^2*(pu1)^2-1 *(pu1)^2 by XCMPLX_1:29
  .= (pu2)^2*((pu2)^2-1)+(pu2)^2*(pu1)^2-1 *(pu1)^2 by XCMPLX_1:40
  .= (pu2)^2*((pu2)^2-1)+((pu2)^2*(pu1)^2-1 *(pu1)^2) by XCMPLX_1:29
  .= ((pu2)^2-1)*(pu2)^2+((pu2)^2-1)*(pu1)^2 by XCMPLX_1:40
  .= ((pu2)^2-1)*((pu2)^2+(pu1)^2) by XCMPLX_1:8;
end;

Lm18:now let px1 be real number;
 assume (px1)^2-1=0;
 then (px1-1)*(px1+1)=0 by SQUARE_1:59,67;
 then px1-1=0 or px1+1=0 by XCMPLX_1:6;
 then px1=0+1 or px1+1=0 by XCMPLX_1:27;
 then px1=1 or px1=0-1 by XCMPLX_1:26;
 hence px1=1 or px1=-1;
end;

theorem for f,g being map of I[01],TOP-REAL 2,
  C0,KXP,KXN,KYP,KYN being Subset of TOP-REAL 2,
  O,I being Point of I[01] st O=0 & I=1 &
  f is continuous one-to-one &
  g is continuous one-to-one &
  C0={p: |.p.|<=1}&
  KXP={q1 where q1 is Point of TOP-REAL 2:
           |.q1.|=1 & q1`2<=q1`1 & q1`2>=-q1`1} &
  KXN={q2 where q2 is Point of TOP-REAL 2:
           |.q2.|=1 & q2`2>=q2`1 & q2`2<=-q2`1} &
  KYP={q3 where q3 is Point of TOP-REAL 2:
           |.q3.|=1 & q3`2>=q3`1 & q3`2>=-q3`1} &
  KYN={q4 where q4 is Point of TOP-REAL 2:
           |.q4.|=1 & q4`2<=q4`1 & q4`2<=-q4`1} &
  f.O in KXN & f.I in KXP &
  g.O in KYN & g.I in KYP &
  rng f c= C0 & rng g c= C0
   holds rng f meets rng g
proof let f,g be map of I[01],TOP-REAL 2,
  C0,KXP,KXN,KYP,KYN be Subset of TOP-REAL 2,
  O,I be Point of I[01];
  assume A1: O=0 & I=1 &
  f is continuous one-to-one & g is continuous one-to-one &
  C0={p: |.p.|<=1}&
  KXP={q1 where q1 is Point of TOP-REAL 2:
  |.q1.|=1 & q1`2<=q1`1 & q1`2>=-q1`1} &
  KXN={q2 where q2 is Point of TOP-REAL 2:
  |.q2.|=1 & q2`2>=q2`1 & q2`2<=-q2`1} &
  KYP={q3 where q3 is Point of TOP-REAL 2:
           |.q3.|=1 & q3`2>=q3`1 & q3`2>=-q3`1} &
  KYN={q4 where q4 is Point of TOP-REAL 2:
           |.q4.|=1 & q4`2<=q4`1 & q4`2<=-q4`1} &
  f.O in KXN & f.I in KXP &
  g.O in KYN & g.I in KYP &
  rng f c= C0 & rng g c= C0;
      Sq_Circ"*f is Function of the carrier of I[01],
           the carrier of TOP-REAL 2 by Th39,FUNCT_2:19;
    then reconsider ff=Sq_Circ"*f as map of I[01],TOP-REAL 2;
      Sq_Circ"*g is Function of the carrier of I[01],
           the carrier of TOP-REAL 2 by Th39,FUNCT_2:19;
    then reconsider gg=Sq_Circ"*g as map of I[01],TOP-REAL 2;
    consider h1 being map of (TOP-REAL 2),(TOP-REAL 2)
      such that A2:h1=(Sq_Circ") & h1 is continuous by Th52;
    A3:dom ff=the carrier of I[01] by FUNCT_2:def 1;
    A4:dom gg=the carrier of I[01] by FUNCT_2:def 1;
    A5:dom f=the carrier of I[01] by FUNCT_2:def 1;
    A6:dom g=the carrier of I[01] by FUNCT_2:def 1;
    A7:ff is continuous by A1,A2,TOPS_2:58;
    A8:ff is one-to-one by A1,Lm15,FUNCT_1:46;
    A9:gg is continuous by A1,A2,TOPS_2:58;
    A10:gg is one-to-one by A1,Lm15,FUNCT_1:46;
    A11: (ff.O)=(Sq_Circ").(f.O) by A3,FUNCT_1:22;
    consider p1 being Point of TOP-REAL 2 such that
    A12:  f.O=p1 &( |.p1.|=1 & p1`2>=p1`1 & p1`2<=-p1`1) by A1;
    A13:p1<>0.REAL 2 & (p1`2<=p1`1 & -p1`1<=p1`2 or p1`2>=p1`1 & p1`2<=-p1`1)
                            by A12,TOPRNS_1:24;
    then A14:Sq_Circ".p1=|[p1`1*sqrt(1+(p1`2/p1`1)^2),p1`2*sqrt(1+(p1`2/p1`1)^2
)]|
                                 by Th38;
    A15: (ff.O)`1=-1 & (ff.I)`1=1 & (gg.O)`2=-1 & (gg.I)`2=1
    proof
        set px=ff.O;set q=px;
        A16:Sq_Circ".p1=q by A3,A12,FUNCT_1:22;
        A17: px`1 = p1`1*sqrt(1+(p1`2/p1`1)^2) &
         px`2 = p1`2*sqrt(1+(p1`2/p1`1)^2) by A11,A12,A14,EUCLID:56;
          1+(p1`2/p1`1)^2>0 by Lm1;
        then A18:sqrt(1+(p1`2/p1`1)^2)>0 by SQUARE_1:93;
        A19:now assume
A20:        px`1=0 & px`2=0;
          then A21:p1`1=0 by A17,A18,XCMPLX_1:6;
            p1`2=0 by A17,A18,A20,XCMPLX_1:6;
         hence contradiction by A13,A21,EUCLID:57,58;
        end;
          p1`2<=p1`1 & -p1`1<=p1`2 or p1`2>=p1`1 &
        p1`2*sqrt(1+(p1`2/p1`1)^2) <= (-p1`1)*sqrt(1+(p1`2/p1`1)^2)
                             by A12,A18,AXIOMS:25;
     then p1`2<=p1`1 & (-p1`1)*sqrt(1+(p1`2/p1`1)^2) <= p1`2*sqrt(1+(p1`2/p1`1
)^2)
           or px`2>=px`1 & px`2<=-px`1 by A17,A18,AXIOMS:25,XCMPLX_1:175;
        then A22:px`2<=px`1 & -px`1<=px`2 or px`2>=px`1 & px`2<=-px`1
                                by A17,A18,AXIOMS:25,XCMPLX_1:175;
        A23:p1=Sq_Circ.px by A16,Th54,FUNCT_1:54;
        A24:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|
                                 by A19,A22,Def1,JGRAPH_2:11;
        A25: (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`1
         = q`1/sqrt(1+(q`2/q`1)^2) &
         (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`2
         = q`2/sqrt(1+(q`2/q`1)^2) by EUCLID:56;
        A26:1+(q`2/q`1)^2>0 by Lm1;
        then A27:sqrt(1+(q`2/q`1)^2)>0 by SQUARE_1:93;
         px`1<>0 by A19,A22;
        then A28: (px`1)^2<>0 by SQUARE_1:73;
          (|.p1.|)^2= (q`1/sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by A23,A24,A25,JGRAPH_1:46
               .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
           .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
               .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by A26,SQUARE_1:def 4
               .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(1+(q`2/q`1)^2)
                              by A26,SQUARE_1:def 4
               .= ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2) by XCMPLX_1:63;
        then ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2)*(1+(q`2/q`1)^2)=1 *(1+(q`2/q`1)
^2)
                              by A12,SQUARE_1:59;
         then (q`1)^2+(q`2)^2=1+(q`2/q`1)^2 by A26,XCMPLX_1:88;
         then (px`1)^2+(px`2)^2=1+(px`2)^2/(px`1)^2 by SQUARE_1:69;
         then (px`1)^2+(px`2)^2-1=(px`2)^2/(px`1)^2 by XCMPLX_1:26;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2=(px`2)^2 by A28,XCMPLX_1:88;
         then A29:((px`1)^2-1)*((px`1)^2+(px`2)^2)=0 by Lm17;
           ((px`1)^2+(px`2)^2)<>0 by A19,COMPLEX1:2;
         then A30: ((px`1)^2-1)=0 by A29,XCMPLX_1:6;
         A31: now assume A32: px`1=1;
           then A33:p1`1>0 by A23,A24,A25,A27,REAL_2:127;
             -p1`2>=--p1`1 by A12,REAL_1:50;
           then -p1`2>0 by A23,A24,A25,A27,A32,REAL_2:127;
           then --p1`2<-0 by REAL_1:50;
          hence contradiction by A12,A33,AXIOMS:22;
         end;
    A34: (ff.I)=(Sq_Circ").(f.I) by A3,FUNCT_1:22;
    consider p2 being Point of TOP-REAL 2 such that
    A35:  f.I=p2 &(|.p2.|=1 & p2`2<=p2`1 & p2`2>=-p2`1) by A1;
    A36:p2<>0.REAL 2 & (p2`2<=p2`1 & -p2`1<=p2`2 or p2`2>=p2`1 & p2`2<=-p2`1)
                            by A35,TOPRNS_1:24;
    then A37:Sq_Circ".p2=|[p2`1*sqrt(1+(p2`2/p2`1)^2),p2`2*sqrt(1+(p2`2/p2`1)^2
)]|
                                 by Th38;
        set py=ff.I;
        A38: py`1 = p2`1*sqrt(1+(p2`2/p2`1)^2) &
         py`2 = p2`2*sqrt(1+(p2`2/p2`1)^2) by A34,A35,A37,EUCLID:56;
          1+(p2`2/p2`1)^2>0 by Lm1;
        then A39:sqrt(1+(p2`2/p2`1)^2)>0 by SQUARE_1:93;
        A40:now assume
A41:        py`1=0 & py`2=0;
          then A42:p2`1=0 by A38,A39,XCMPLX_1:6;
            p2`2=0 by A38,A39,A41,XCMPLX_1:6;
         hence contradiction by A36,A42,EUCLID:57,58;
        end;
        A43: now
       p2`2<=p2`1 & (-p2`1)*sqrt(1+(p2`2/p2`1)^2) <= p2`2*sqrt(1+(p2`2/p2`1)^2)
           or py`2>=py`1 & py`2<=-py`1 by A35,A39,AXIOMS:25;
           hence
          p2`2*sqrt(1+(p2`2/p2`1)^2) <= p2`1*sqrt(1+(p2`2/p2`1)^2) & -py`1<=py
`2
           or py`2>=py`1 & py`2<=-py`1 by A38,A39,AXIOMS:25,XCMPLX_1:175;
        end;
        A44:p2=Sq_Circ.py by A34,A35,Th54,FUNCT_1:54;
     A45:Sq_Circ.py=|[py`1/sqrt(1+(py`2/py`1)^2),py`2/sqrt(1+(py`2/py`1)^2)]|
                                 by A38,A40,A43,Def1,JGRAPH_2:11;
        A46: (|[py`1/sqrt(1+(py`2/py`1)^2),py`2/sqrt(1+(py`2/py`1)^2)]|)`1
         = py`1/sqrt(1+(py`2/py`1)^2) &
         (|[py`1/sqrt(1+(py`2/py`1)^2),py`2/sqrt(1+(py`2/py`1)^2)]|)`2
         = py`2/sqrt(1+(py`2/py`1)^2) by EUCLID:56;
        A47:1+(py`2/py`1)^2>0 by Lm1;
        then A48:sqrt(1+(py`2/py`1)^2)>0 by SQUARE_1:93;
         py`1<>0 by A38,A40,A43;
        then A49: (py`1)^2<>0 by SQUARE_1:73;
      (|.p2.|)^2= (py`1/sqrt(1+(py`2/py`1)^2))^2+(py`2/sqrt(1+(py`2/py`1)^2))^2
                              by A44,A45,A46,JGRAPH_1:46
         .= (py`1)^2/(sqrt(1+(py`2/py`1)^2))^2+(py`2/sqrt(1+(py`2/py`1)^2))^2
                              by SQUARE_1:69
               .= (py`1)^2/(sqrt(1+(py`2/py`1)^2))^2
                         +(py`2)^2/(sqrt(1+(py`2/py`1)^2))^2 by SQUARE_1:69
               .= (py`1)^2/(1+(py`2/py`1)^2)+(py`2)^2/(sqrt(1+(py`2/py`1)^2))^2
                              by A47,SQUARE_1:def 4
               .= (py`1)^2/(1+(py`2/py`1)^2)+(py`2)^2/(1+(py`2/py`1)^2)
                              by A47,SQUARE_1:def 4
               .= ((py`1)^2+(py`2)^2)/(1+(py`2/py`1)^2) by XCMPLX_1:63;
       then ((py`1)^2+(py`2)^2)/(1+(py`2/py`1)^2)*(1+(py`2/py`1)^2)
                =1 *(1+(py`2/py`1)^2) by A35,SQUARE_1:59;
        then ((py`1)^2+(py`2)^2)=(1+(py`2/py`1)^2) by A47,XCMPLX_1:88;
         then (py`1)^2+(py`2)^2=1+(py`2)^2/(py`1)^2 by SQUARE_1:69;
         then (py`1)^2+(py`2)^2-1=(py`2)^2/(py`1)^2 by XCMPLX_1:26;
         then ((py`1)^2+(py`2)^2-1)*(py`1)^2=(py`2)^2 by A49,XCMPLX_1:88;
         then A50:((py`1)^2-1)*((py`1)^2+(py`2)^2)=0 by Lm17;
           ((py`1)^2+(py`2)^2)<>0 by A40,COMPLEX1:2;
         then A51: ((py`1)^2-1)=0 by A50,XCMPLX_1:6;
         A52: now assume A53: py`1=-1;
           then A54:p2`1<0 by A44,A45,A46,A48,REAL_2:128;
             -p2`2<=--p2`1 by A35,REAL_1:50;
           then -p2`2<0 by A44,A45,A46,A48,A53,REAL_2:128;
           then --p2`2>-0 by REAL_1:50;
          hence contradiction by A35,A54,AXIOMS:22;
         end;
    A55: (gg.O)=(Sq_Circ").(g.O) by A4,FUNCT_1:22;
    consider p3 being Point of TOP-REAL 2 such that
    A56:  g.O=p3 &( |.p3.|=1 & p3`2<=p3`1 & p3`2<=-p3`1) by A1;
A57:  -p3`2>=--p3`1 by A56,REAL_1:50;
    then A58:p3<>0.REAL 2 & (p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 & p3`1<=-p3
`2)
                                 by A56,TOPRNS_1:24;
   then A59:Sq_Circ".p3=|[p3`1*sqrt(1+(p3`1/p3`2)^2),p3`2*sqrt(1+(p3`1/p3`2)^2)
]|
                                 by Th40;
        set pz=gg.O;
        A60: pz`2 = p3`2*sqrt(1+(p3`1/p3`2)^2) &
         pz`1 = p3`1*sqrt(1+(p3`1/p3`2)^2) by A55,A56,A59,EUCLID:56;
          1+(p3`1/p3`2)^2>0 by Lm1;
        then A61:sqrt(1+(p3`1/p3`2)^2)>0 by SQUARE_1:93;
        A62:now assume
A63:        pz`2=0 & pz`1=0;
          then A64:p3`2=0 by A60,A61,XCMPLX_1:6;
            p3`1=0 by A60,A61,A63,XCMPLX_1:6;
         hence contradiction by A58,A64,EUCLID:57,58;
        end;
        A65: now p3`1<=p3`2 & -p3`2<=p3`1 or p3`1>=p3`2 &
        p3`1*sqrt(1+(p3`1/p3`2)^2) <= (-p3`2)*sqrt(1+(p3`1/p3`2)^2)
                             by A56,A57,A61,AXIOMS:25;
     then p3`1<=p3`2 & (-p3`2)*sqrt(1+(p3`1/p3`2)^2) <= p3`1*sqrt(1+(p3`1/p3`2
)^2)
           or pz`1>=pz`2 & pz`1<=-pz`2 by A60,A61,AXIOMS:25,XCMPLX_1:175;
           hence
         p3`1*sqrt(1+(p3`1/p3`2)^2) <= p3`2*sqrt(1+(p3`1/p3`2)^2) & -pz`2<=pz`1
           or pz`1>=pz`2 & pz`1<=-pz`2 by A60,A61,AXIOMS:25,XCMPLX_1:175;
        end;
        A66:p3=Sq_Circ.pz by A55,A56,Th54,FUNCT_1:54;
     A67:Sq_Circ.pz=|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|
                                 by A60,A62,A65,Th14,JGRAPH_2:11;
        A68: (|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|)`2
         = pz`2/sqrt(1+(pz`1/pz`2)^2) &
         (|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|)`1
         = pz`1/sqrt(1+(pz`1/pz`2)^2) by EUCLID:56;
        A69:1+(pz`1/pz`2)^2>0 by Lm1;
        then A70:sqrt(1+(pz`1/pz`2)^2)>0 by SQUARE_1:93;
         pz`2<>0 by A60,A62,A65;
        then A71: (pz`2)^2<>0 by SQUARE_1:73;
  (|.p3.|)^2= (pz`2/sqrt(1+(pz`1/pz`2)^2))^2+(pz`1/sqrt(1+(pz`1/pz`2)^2))^2
                              by A66,A67,A68,JGRAPH_1:46
        .= (pz`2)^2/(sqrt(1+(pz`1/pz`2)^2))^2+(pz`1/sqrt(1+(pz`1/pz`2)^2))^2
                              by SQUARE_1:69
        .= (pz`2)^2/(sqrt(1+(pz`1/pz`2)^2))^2
                      +(pz`1)^2/(sqrt(1+(pz`1/pz`2)^2))^2 by SQUARE_1:69
        .= (pz`2)^2/(1+(pz`1/pz`2)^2)+(pz`1)^2/(sqrt(1+(pz`1/pz`2)^2))^2
                              by A69,SQUARE_1:def 4
        .= (pz`2)^2/(1+(pz`1/pz`2)^2)+(pz`1)^2/(1+(pz`1/pz`2)^2)
                              by A69,SQUARE_1:def 4
        .= ((pz`2)^2+(pz`1)^2)/(1+(pz`1/pz`2)^2) by XCMPLX_1:63;
  then ((pz`2)^2+(pz`1)^2)/(1+(pz`1/pz`2)^2)*(1+(pz`1/pz`2)^2)=1 *(1+(pz`1/pz
`2)^2)
                           by A56,SQUARE_1:59;
        then ((pz`2)^2+(pz`1)^2)=(1+(pz`1/pz`2)^2) by A69,XCMPLX_1:88;
         then (pz`2)^2+(pz`1)^2=1+(pz`1)^2/(pz`2)^2 by SQUARE_1:69;
         then (pz`2)^2+(pz`1)^2-1=(pz`1)^2/(pz`2)^2 by XCMPLX_1:26;
         then ((pz`2)^2+(pz`1)^2-1)*(pz`2)^2=(pz`1)^2 by A71,XCMPLX_1:88;
         then A72:((pz`2)^2-1)*((pz`2)^2+(pz`1)^2)=0 by Lm17;
           ((pz`2)^2+(pz`1)^2)<>0 by A62,COMPLEX1:2;
         then A73: (pz`2)^2-1=0 by A72,XCMPLX_1:6;
         A74: now assume A75: pz`2=1;
           then A76:p3`2>0 by A66,A67,A68,A70,REAL_2:127;
            -p3`1>0 by A56,A66,A67,A68,A70,A75,REAL_2:127;
           then --p3`1<-0 by REAL_1:50;
          hence contradiction by A56,A76,AXIOMS:22;
         end;
    A77: (gg.I)=(Sq_Circ").(g.I) by A4,FUNCT_1:22;
    consider p4 being Point of TOP-REAL 2 such that
    A78:  g.I=p4 &(|.p4.|=1 & p4`2>=p4`1 & p4`2>=-p4`1) by A1;
    A79: -p4`2<=--p4`1 by A78,REAL_1:50;
    then A80:p4<>0.REAL 2 &
          (p4`1<=p4`2 & -p4`2<=p4`1 or p4`1>=p4`2 & p4`1<=-p4`2)
                      by A78,TOPRNS_1:24;
    then A81:Sq_Circ".p4=|[p4`1*sqrt(1+(p4`1/p4`2)^2),p4`2*sqrt(1+(p4`1/p4`2)^2
)]|
                                 by Th40;
        set pu=gg.I;
        A82: pu`2 = p4`2*sqrt(1+(p4`1/p4`2)^2) &
         pu`1 = p4`1*sqrt(1+(p4`1/p4`2)^2) by A77,A78,A81,EUCLID:56;
          1+(p4`1/p4`2)^2>0 by Lm1;
        then A83:sqrt(1+(p4`1/p4`2)^2)>0 by SQUARE_1:93;
        A84:now assume
A85:        pu`2=0 & pu`1=0;
          then A86:p4`2=0 by A82,A83,XCMPLX_1:6;
            p4`1=0 by A82,A83,A85,XCMPLX_1:6;
         hence contradiction by A80,A86,EUCLID:57,58;
        end;
        A87: now
       p4`1<=p4`2 & (-p4`2)*sqrt(1+(p4`1/p4`2)^2) <= p4`1*sqrt(1+(p4`1/p4`2)^2)
           or pu`1>=pu`2 & pu`1<=-pu`2 by A78,A79,A83,AXIOMS:25;hence
         p4`1*sqrt(1+(p4`1/p4`2)^2) <= p4`2*sqrt(1+(p4`1/p4`2)^2) & -pu`2<=pu`1
           or pu`1>=pu`2 & pu`1<=-pu`2 by A82,A83,AXIOMS:25,XCMPLX_1:175;
        end;
        A88:p4=Sq_Circ.pu by A77,A78,Th54,FUNCT_1:54;
    A89:Sq_Circ.pu=|[pu`1/sqrt(1+(pu`1/pu`2)^2),pu`2/sqrt(1+(pu`1/pu`2)^2)]|
                                 by A82,A84,A87,Th14,JGRAPH_2:11;
        A90: (|[pu`1/sqrt(1+(pu`1/pu`2)^2),pu`2/sqrt(1+(pu`1/pu`2)^2)]|)`2
         = pu`2/sqrt(1+(pu`1/pu`2)^2) &
         (|[pu`1/sqrt(1+(pu`1/pu`2)^2),pu`2/sqrt(1+(pu`1/pu`2)^2)]|)`1
         = pu`1/sqrt(1+(pu`1/pu`2)^2) by EUCLID:56;
        A91:1+(pu`1/pu`2)^2>0 by Lm1;
        then A92:sqrt(1+(pu`1/pu`2)^2)>0 by SQUARE_1:93;
         pu`2<>0 by A82,A84,A87;
        then A93: (pu`2)^2<>0 by SQUARE_1:73;
      (|.p4.|)^2= (pu`2/sqrt(1+(pu`1/pu`2)^2))^2+(pu`1/sqrt(1+(pu`1/pu`2)^2))^2
                              by A88,A89,A90,JGRAPH_1:46
        .= (pu`2)^2/(sqrt(1+(pu`1/pu`2)^2))^2+(pu`1/sqrt(1+(pu`1/pu`2)^2))^2
                              by SQUARE_1:69
               .= (pu`2)^2/(sqrt(1+(pu`1/pu`2)^2))^2
                             +(pu`1)^2/(sqrt(1+(pu`1/pu`2)^2))^2
                              by SQUARE_1:69
            .= (pu`2)^2/(1+(pu`1/pu`2)^2)+(pu`1)^2/(sqrt(1+(pu`1/pu`2)^2))^2
                              by A91,SQUARE_1:def 4
               .= (pu`2)^2/(1+(pu`1/pu`2)^2)+(pu`1)^2/(1+(pu`1/pu`2)^2)
                              by A91,SQUARE_1:def 4
               .= ((pu`2)^2+(pu`1)^2)/(1+(pu`1/pu`2)^2)
                              by XCMPLX_1:63;
  then ((pu`2)^2+(pu`1)^2)/(1+(pu`1/pu`2)^2)*(1+(pu`1/pu`2)^2)=1 *(1+(pu`1/pu
`2)^2)
                               by A78,SQUARE_1:59;
        then ((pu`2)^2+(pu`1)^2)=(1+(pu`1/pu`2)^2) by A91,XCMPLX_1:88;
         then (pu`2)^2+(pu`1)^2=1+(pu`1)^2/(pu`2)^2 by SQUARE_1:69;
         then (pu`2)^2+(pu`1)^2-1=(pu`1)^2/(pu`2)^2 by XCMPLX_1:26;
         then ((pu`2)^2+(pu`1)^2-1)*(pu`2)^2=(pu`1)^2 by A93,XCMPLX_1:88;
         then A94:((pu`2)^2-1)*((pu`2)^2+(pu`1)^2)=0 by Lm17;
           ((pu`2)^2+(pu`1)^2)<>0 by A84,COMPLEX1:2;
         then A95: ((pu`2)^2-1)=0 by A94,XCMPLX_1:6;
           now assume A96: pu`2=-1;
           then A97:p4`2<0 by A88,A89,A90,A92,REAL_2:128;
            -p4`1<0 by A78,A88,A89,A90,A92,A96,REAL_2:128;
           then --p4`1>-0 by REAL_1:50;
          hence contradiction by A78,A97,AXIOMS:22;
         end;
     hence thesis by A30,A31,A51,A52,A73,A74,A95,Lm18;
     end;
       for r being Point of I[01] holds
     -1<=(ff.r)`1 & (ff.r)`1<=1 & -1<=(gg.r)`1 & (gg.r)`1<=1 &
     -1 <=(ff.r)`2 & (ff.r)`2<=1 & -1 <=(gg.r)`2 & (gg.r)`2<=1
      proof let r be Point of I[01];
        A98: (ff.r)=(Sq_Circ").(f.r) by A3,FUNCT_1:22;
          f.r in rng f by A5,FUNCT_1:12;
        then f.r in C0 by A1;
        then consider p1 being Point of TOP-REAL 2 such that
        A99:  f.r=p1 & |.p1.|<=1 by A1;
       A100:now per cases;
       case p1=0.REAL 2; then ff.r=0.REAL 2 by A98,A99,Th38;
        hence -1<=(ff.r)`1 & (ff.r)`1<=1 & -1 <=(ff.r)`2 & (ff.r)`2<=1
                          by JGRAPH_2:11;
       case
        A101:p1<>0.REAL 2 &
          (p1`2<=p1`1 & -p1`1<=p1`2 or p1`2>=p1`1 & p1`2<=-p1`1);
   then A102:Sq_Circ".p1=|[p1`1*sqrt(1+(p1`2/p1`1)^2),p1`2*sqrt(1+(p1`2/p1`1)^2
)
]|
                                 by Th38;
        set px=ff.r; set q=px;
        A103: px`1 = p1`1*sqrt(1+(p1`2/p1`1)^2) &
        px`2 = p1`2*sqrt(1+(p1`2/p1`1)^2) by A98,A99,A102,EUCLID:56;
          1+(p1`2/p1`1)^2>0 by Lm1;
        then A104:sqrt(1+(p1`2/p1`1)^2)>0 by SQUARE_1:93;
        A105:now assume
A106:        px`1=0 & px`2=0;
          then A107:p1`1=0 by A103,A104,XCMPLX_1:6;
            p1`2=0 by A103,A104,A106,XCMPLX_1:6;
         hence contradiction by A101,A107,EUCLID:57,58;
        end;
          p1`2<=p1`1 & -p1`1<=p1`2 or p1`2>=p1`1 &
        p1`2*sqrt(1+(p1`2/p1`1)^2) <= (-p1`1)*sqrt(1+(p1`2/p1`1)^2)
                             by A101,A104,AXIOMS:25;
     then p1`2<=p1`1 & (-p1`1)*sqrt(1+(p1`2/p1`1)^2) <= p1`2*sqrt(1+(p1`2/p1`1
)^2)
           or px`2>=px`1 & px`2<=-px`1 by A103,A104,AXIOMS:25,XCMPLX_1:175;
        then A108:px`2<=px`1 & -px`1<=px`2 or px`2>=px`1 & px`2<=-px`1
                              by A103,A104,AXIOMS:25,XCMPLX_1:175;
        A109:p1=Sq_Circ.px by A98,A99,Th54,FUNCT_1:54;
        A110:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|
                                 by A105,A108,Def1,JGRAPH_2:11;
        A111: (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`1
         = q`1/sqrt(1+(q`2/q`1)^2) &
         (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`2
         = q`2/sqrt(1+(q`2/q`1)^2) by EUCLID:56;
        A112:(px`1)^2 >=0 by SQUARE_1:72;
        A113:1+(q`2/q`1)^2>0 by Lm1;
          0<= |.p1.| by TOPRNS_1:26;
        then (|.p1.|)^2<=|.p1.| by A99,Th3;
        then A114: (|.p1.|)^2<=1 by A99,AXIOMS:22;
         px`1<>0 by A105,A108;
        then A115: (px`1)^2<>0 by SQUARE_1:73;
          (|.p1.|)^2= (q`1/sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by A109,A110,A111,JGRAPH_1:46
               .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
           .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
               .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by A113,SQUARE_1:def 4
               .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(1+(q`2/q`1)^2)
                              by A113,SQUARE_1:def 4
               .= ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2) by XCMPLX_1:63;
        then ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2)*(1+(q`2/q`1)^2)<=1 *(1+(q`2/q`1
)^2)
                              by A113,A114,AXIOMS:25;
         then (q`1)^2+(q`2)^2<=1+(q`2/q`1)^2 by A113,XCMPLX_1:88;
         then (px`1)^2+(px`2)^2<=1+(px`2)^2/(px`1)^2 by SQUARE_1:69;
         then (px`1)^2+(px`2)^2-1<=(px`2)^2/(px`1)^2 by REAL_1:86;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2<=(px`2)^2/(px`1)^2*(px`1)^2
                              by A112,AXIOMS:25;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2<=(px`2)^2 by A115,XCMPLX_1:88;
         then A116:((px`1)^2-1)*((px`1)^2+(px`2)^2)<=0 by Lm16;
         A117: ((px`1)^2+(px`2)^2)<>0 by A105,COMPLEX1:2;
           (px`2)^2>=0 by SQUARE_1:72;
         then ((px`1)^2+(px`2)^2)>=0+0 by A112,REAL_1:55;
         then A118: (px`1)^2-1<=0 by A116,A117,REAL_2:122;
         then A119:px`1<=1 & px`1>=-1 by Th5;
           now (q`2<=1 & --q`1>=-q`2 or q`2>=-1 & q`2<=-q`1)
                   by A108,A119,AXIOMS:22,REAL_1:50;
         then (q`2<=1 & q`1>=-q`2 or q`2>=-1 & -q`2>=--q`1) by REAL_1:50;
         then (q`2<=1 & 1>=-q`2 or q`2>=-1 & -q`2>=q`1)
                   by A119,AXIOMS:22;
         then (q`2<=1 & -1<=--q`2 or q`2>=-1 & -q`2>=-1)
                   by A119,AXIOMS:22,REAL_1:50;
          hence (q`2<=1 & -1<=q`2 or q`2>=-1 & q`2<=1) by REAL_1:50;
          end;
        hence -1<=(ff.r)`1 & (ff.r)`1<=1 & -1 <=(ff.r)`2 & (ff.r)`2<=1
                         by A118,Th5;
       case
        A120:p1<>0.REAL 2 &
          not(p1`2<=p1`1 & -p1`1<=p1`2 or p1`2>=p1`1 & p1`2<=-p1`1);
    then A121:Sq_Circ".p1=|[p1`1*sqrt(1+(p1`1/p1`2)^2),p1`2*sqrt(1+(p1`1/p1`2)
^2)]|
                                 by Th38;
        A122:p1<>0.REAL 2 &
          (p1`1<=p1`2 & -p1`2<=p1`1 or p1`1>=p1`2 & p1`1<=-p1`2)
                      by A120,JGRAPH_2:23;
        set pz=ff.r;
        A123: pz`2 = p1`2*sqrt(1+(p1`1/p1`2)^2) &
         pz`1 = p1`1*sqrt(1+(p1`1/p1`2)^2) by A98,A99,A121,EUCLID:56;
          1+(p1`1/p1`2)^2>0 by Lm1;
        then A124:sqrt(1+(p1`1/p1`2)^2)>0 by SQUARE_1:93;
        A125:now assume
A126:        pz`2=0 & pz`1=0;
          then p1`2=0 by A123,A124,XCMPLX_1:6;
         hence contradiction by A120,A123,A124,A126,XCMPLX_1:6;
        end;
        A127: now p1`1<=p1`2 & -p1`2<=p1`1 or p1`1>=p1`2 &
        p1`1*sqrt(1+(p1`1/p1`2)^2) <= (-p1`2)*sqrt(1+(p1`1/p1`2)^2)
                             by A122,A124,AXIOMS:25;
     then p1`1<=p1`2 & (-p1`2)*sqrt(1+(p1`1/p1`2)^2) <= p1`1*sqrt(1+(p1`1/p1`2
)^2)
           or pz`1>=pz`2 & pz`1<=-pz`2 by A123,A124,AXIOMS:25,XCMPLX_1:175;
           hence
         p1`1*sqrt(1+(p1`1/p1`2)^2) <= p1`2*sqrt(1+(p1`1/p1`2)^2) & -pz`2<=pz`1
           or pz`1>=pz`2 & pz`1<=-pz`2 by A123,A124,AXIOMS:25,XCMPLX_1:175;
        end;
        A128:p1=Sq_Circ.pz by A98,A99,Th54,FUNCT_1:54;
     A129:Sq_Circ.pz=|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|
                                 by A123,A125,A127,Th14,JGRAPH_2:11;
        A130: (|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|)`2
         = pz`2/sqrt(1+(pz`1/pz`2)^2) &
         (|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|)`1
         = pz`1/sqrt(1+(pz`1/pz`2)^2) by EUCLID:56;
        A131:(pz`2)^2 >=0 by SQUARE_1:72;
        A132:1+(pz`1/pz`2)^2>0 by Lm1;
          0<= |.p1.| by TOPRNS_1:26;
        then (|.p1.|)^2<=|.p1.| by A99,Th3;
        then A133: (|.p1.|)^2<=1 by A99,AXIOMS:22;
         pz`2<>0 by A123,A125,A127;
        then A134: (pz`2)^2<>0 by SQUARE_1:73;
  (|.p1.|)^2= (pz`2/sqrt(1+(pz`1/pz`2)^2))^2+(pz`1/sqrt(1+(pz`1/pz`2)^2))^2
                              by A128,A129,A130,JGRAPH_1:46
        .= (pz`2)^2/(sqrt(1+(pz`1/pz`2)^2))^2+(pz`1/sqrt(1+(pz`1/pz`2)^2))^2
                              by SQUARE_1:69
               .= (pz`2)^2/(sqrt(1+(pz`1/pz`2)^2))^2
                      +(pz`1)^2/(sqrt(1+(pz`1/pz`2)^2))^2 by SQUARE_1:69
               .= (pz`2)^2/(1+(pz`1/pz`2)^2)+(pz`1)^2/(sqrt(1+(pz`1/pz`2)^2))^2
                              by A132,SQUARE_1:def 4
               .= (pz`2)^2/(1+(pz`1/pz`2)^2)+(pz`1)^2/(1+(pz`1/pz`2)^2)
                              by A132,SQUARE_1:def 4
               .= ((pz`2)^2+(pz`1)^2)/(1+(pz`1/pz`2)^2) by XCMPLX_1:63;
        then ((pz`2)^2+(pz`1)^2)/(1+(pz`1/pz`2)^2)*(1+(pz`1/pz`2)^2)
            <=1 *(1+(pz`1/pz`2)^2) by A132,A133,AXIOMS:25;
        then ((pz`2)^2+(pz`1)^2)<=(1+(pz`1/pz`2)^2) by A132,XCMPLX_1:88;
         then (pz`2)^2+(pz`1)^2<=1+(pz`1)^2/(pz`2)^2 by SQUARE_1:69;
         then (pz`2)^2+(pz`1)^2-1<=(pz`1)^2/(pz`2)^2 by REAL_1:86;
         then ((pz`2)^2+(pz`1)^2-1)*(pz`2)^2<=(pz`1)^2/(pz`2)^2*(pz`2)^2
                              by A131,AXIOMS:25;
         then ((pz`2)^2+(pz`1)^2-1)*(pz`2)^2<=(pz`1)^2 by A134,XCMPLX_1:88;
         then A135:((pz`2)^2-1)*((pz`2)^2+(pz`1)^2)<=0 by Lm16;
         A136: ((pz`2)^2+(pz`1)^2)<>0 by A125,COMPLEX1:2;
           (pz`1)^2>=0 by SQUARE_1:72;
         then ((pz`2)^2+(pz`1)^2)>=0+0 by A131,REAL_1:55;
         then A137: (pz`2)^2-1<=0 by A135,A136,REAL_2:122;
         then A138:pz`2<=1 & pz`2>=-1 by Th5;
         then (pz`1<=1 & --pz`2>=-pz`1 or pz`1>=-1 & pz`1<=-pz`2)
                   by A123,A127,AXIOMS:22,REAL_1:50;
         then (pz`1<=1 & 1>=-pz`1 or pz`1>=-1 & -pz`1>=--pz`2)
                   by A138,AXIOMS:22,REAL_1:50;
         then (pz`1<=1 & 1>=-pz`1 or pz`1>=-1 & -pz`1>=-1) by A138,AXIOMS:22;
         then (pz`1<=1 & -1<=--pz`1 or pz`1>=-1 & pz`1<=1) by REAL_1:50;
        hence -1<=(ff.r)`1 & (ff.r)`1<=1 & -1 <=(ff.r)`2 & (ff.r)`2<=1 by A137,
Th5;
       end;
        A139: (gg.r)=(Sq_Circ").(g.r) by A4,FUNCT_1:22;
          g.r in rng g by A6,FUNCT_1:12;
        then g.r in C0 by A1;
        then consider p2 being Point of TOP-REAL 2 such that
        A140:  g.r=p2 & |.p2.|<=1 by A1;
         now per cases;
       case p2=0.REAL 2; then gg.r=0.REAL 2 by A139,A140,Th38;
        hence -1<=(gg.r)`1 & (gg.r)`1<=1 & -1 <=(gg.r)`2 & (gg.r)`2<=1
                            by JGRAPH_2:11;
       case
        A141:p2<>0.REAL 2 &
          (p2`2<=p2`1 & -p2`1<=p2`2 or p2`2>=p2`1 & p2`2<=-p2`1);
   then A142:Sq_Circ".p2=|[p2`1*sqrt(1+(p2`2/p2`1)^2),p2`2*sqrt(1+(p2`2/p2`1)^2
)]|
                                 by Th38;
        set px=gg.r; set q=px;
        A143: px`1 = p2`1*sqrt(1+(p2`2/p2`1)^2) &
         px`2 = p2`2*sqrt(1+(p2`2/p2`1)^2) by A139,A140,A142,EUCLID:56;
          1+(p2`2/p2`1)^2>0 by Lm1;
        then A144:sqrt(1+(p2`2/p2`1)^2)>0 by SQUARE_1:93;
        A145:now assume
A146:        px`1=0 & px`2=0;
          then A147:p2`1=0 by A143,A144,XCMPLX_1:6;
            p2`2=0 by A143,A144,A146,XCMPLX_1:6;
         hence contradiction by A141,A147,EUCLID:57,58;
        end;
        A148: now
          p2`2<=p2`1 & -p2`1<=p2`2 or p2`2>=p2`1 &
        p2`2*sqrt(1+(p2`2/p2`1)^2) <= (-p2`1)*sqrt(1+(p2`2/p2`1)^2)
                             by A141,A144,AXIOMS:25;
     then p2`2<=p2`1 & (-p2`1)*sqrt(1+(p2`2/p2`1)^2) <= p2`2*sqrt(1+(p2`2/p2`1
)^2)
           or px`2>=px`1 & px`2<=-px`1 by A143,A144,AXIOMS:25,XCMPLX_1:175
;hence
          p2`2*sqrt(1+(p2`2/p2`1)^2) <= p2`1*sqrt(1+(p2`2/p2`1)^2) & -px`1<=px
`2
           or px`2>=px`1 & px`2<=-px`1 by A143,A144,AXIOMS:25,XCMPLX_1:175;
        end;
        A149:p2=Sq_Circ.px by A139,A140,Th54,FUNCT_1:54;
        A150:Sq_Circ.q=|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|
                                 by A143,A145,A148,Def1,JGRAPH_2:11;
        A151: (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`1
         = q`1/sqrt(1+(q`2/q`1)^2) &
         (|[q`1/sqrt(1+(q`2/q`1)^2),q`2/sqrt(1+(q`2/q`1)^2)]|)`2
         = q`2/sqrt(1+(q`2/q`1)^2) by EUCLID:56;
        A152:(px`1)^2 >=0 by SQUARE_1:72;
        A153:1+(q`2/q`1)^2>0 by Lm1;
          0<= |.p2.| by TOPRNS_1:26;
        then (|.p2.|)^2<=|.p2.| by A140,Th3;
        then A154: (|.p2.|)^2<=1 by A140,AXIOMS:22;
         px`1<>0 by A143,A145,A148;
        then A155: (px`1)^2<>0 by SQUARE_1:73;
          (|.p2.|)^2= (q`1/sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by A149,A150,A151,JGRAPH_1:46
           .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2/sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
           .= (q`1)^2/(sqrt(1+(q`2/q`1)^2))^2+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by SQUARE_1:69
           .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(sqrt(1+(q`2/q`1)^2))^2
                              by A153,SQUARE_1:def 4
           .= (q`1)^2/(1+(q`2/q`1)^2)+(q`2)^2/(1+(q`2/q`1)^2)
                              by A153,SQUARE_1:def 4
           .= ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2) by XCMPLX_1:63;
        then ((q`1)^2+(q`2)^2)/(1+(q`2/q`1)^2)*(1+(q`2/q`1)^2)<=1 *(1+(q`2/q`1
)^2)
                              by A153,A154,AXIOMS:25;
        then ((q`1)^2+(q`2)^2)<=(1+(q`2/q`1)^2) by A153,XCMPLX_1:88;
         then (px`1)^2+(px`2)^2<=1+(px`2)^2/(px`1)^2 by SQUARE_1:69;
         then (px`1)^2+(px`2)^2-1<=(px`2)^2/(px`1)^2 by REAL_1:86;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2<=(px`2)^2/(px`1)^2*(px`1)^2
                              by A152,AXIOMS:25;
         then ((px`1)^2+(px`2)^2-1)*(px`1)^2<=(px`2)^2 by A155,XCMPLX_1:88;
         then A156:((px`1)^2-1)*((px`1)^2+(px`2)^2)<=0 by Lm16;
         A157: ((px`1)^2+(px`2)^2)<>0 by A145,COMPLEX1:2;
           (px`2)^2>=0 by SQUARE_1:72;
         then ((px`1)^2+(px`2)^2)>=0+0 by A152,REAL_1:55;
         then A158: ((px`1)^2-1)<=0 by A156,A157,REAL_2:122;
         then A159:px`1<=1 & px`1>=-1 by Th5;
           now (q`2<=1 & --q`1>=-q`2 or q`2>=-1 & q`2<=-q`1)
                   by A143,A148,A159,AXIOMS:22,REAL_1:50;
         then (q`2<=1 & q`1>=-q`2 or q`2>=-1 & -q`2>=--q`1) by REAL_1:50;
         then (q`2<=1 & 1>=-q`2 or q`2>=-1 & -q`2>=q`1)
                   by A159,AXIOMS:22;
       then (q`2<=1 & -1<=--q`2 or q`2>=-1 & -q`2>=-1) by A159,AXIOMS:22,REAL_1
:50;
          hence (q`2<=1 & -1<=q`2 or q`2>=-1 & q`2<=1) by REAL_1:50;
          end;
        hence -1<=(gg.r)`1 & (gg.r)`1<=1 & -1 <=(gg.r)`2 & (gg.r)`2<=1 by A158,
Th5;
       case
        A160:p2<>0.REAL 2 &
          not(p2`2<=p2`1 & -p2`1<=p2`2 or p2`2>=p2`1 & p2`2<=-p2`1);
   then A161:Sq_Circ".p2=|[p2`1*sqrt(1+(p2`1/p2`2)^2),p2`2*sqrt(1+(p2`1/p2`2)^2
)]|
                                 by Th38;
        A162:p2<>0.REAL 2 &
          (p2`1<=p2`2 & -p2`2<=p2`1 or p2`1>=p2`2 & p2`1<=-p2`2)
                      by A160,JGRAPH_2:23;
        set pz=gg.r;
        A163: pz`2 = p2`2*sqrt(1+(p2`1/p2`2)^2) &
         pz`1 = p2`1*sqrt(1+(p2`1/p2`2)^2) by A139,A140,A161,EUCLID:56;
          1+(p2`1/p2`2)^2>0 by Lm1;
        then A164:sqrt(1+(p2`1/p2`2)^2)>0 by SQUARE_1:93;
        A165:now assume
A166:        pz`2=0 & pz`1=0;
          then p2`2=0 by A163,A164,XCMPLX_1:6;
         hence contradiction by A160,A163,A164,A166,XCMPLX_1:6;
        end;
        A167: now p2`1<=p2`2 & -p2`2<=p2`1 or p2`1>=p2`2 &
        p2`1*sqrt(1+(p2`1/p2`2)^2) <= (-p2`2)*sqrt(1+(p2`1/p2`2)^2)
                             by A162,A164,AXIOMS:25;
    then p2`1<=p2`2 & (-p2`2)*sqrt(1+(p2`1/p2`2)^2) <= p2`1*sqrt(1+(p2`1/p2`2)
^2)
           or pz`1>=pz`2 & pz`1<=-pz`2 by A163,A164,AXIOMS:25,XCMPLX_1:175;
           hence
         p2`1*sqrt(1+(p2`1/p2`2)^2) <= p2`2*sqrt(1+(p2`1/p2`2)^2) & -pz`2<=pz`1
           or pz`1>=pz`2 & pz`1<=-pz`2 by A163,A164,AXIOMS:25,XCMPLX_1:175;
        end;
        A168:p2=Sq_Circ.pz by A139,A140,Th54,FUNCT_1:54;
    A169:Sq_Circ.pz=|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|
                                 by A163,A165,A167,Th14,JGRAPH_2:11;
        A170: (|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|)`2
         = pz`2/sqrt(1+(pz`1/pz`2)^2) &
         (|[pz`1/sqrt(1+(pz`1/pz`2)^2),pz`2/sqrt(1+(pz`1/pz`2)^2)]|)`1
         = pz`1/sqrt(1+(pz`1/pz`2)^2) by EUCLID:56;
        A171:(pz`2)^2 >=0 by SQUARE_1:72;
        A172:1+(pz`1/pz`2)^2>0 by Lm1;
          0<= |.p2.| by TOPRNS_1:26;
        then (|.p2.|)^2<=|.p2.| by A140,Th3;
        then A173: (|.p2.|)^2<=1 by A140,AXIOMS:22;
         pz`2<>0 by A163,A165,A167;
        then A174: (pz`2)^2<>0 by SQUARE_1:73;
  (|.p2.|)^2= (pz`2/sqrt(1+(pz`1/pz`2)^2))^2+(pz`1/sqrt(1+(pz`1/pz`2)^2))^2
                              by A168,A169,A170,JGRAPH_1:46
        .= (pz`2)^2/(sqrt(1+(pz`1/pz`2)^2))^2+(pz`1/sqrt(1+(pz`1/pz`2)^2))^2
                              by SQUARE_1:69
               .= (pz`2)^2/(sqrt(1+(pz`1/pz`2)^2))^2
                      +(pz`1)^2/(sqrt(1+(pz`1/pz`2)^2))^2 by SQUARE_1:69
               .= (pz`2)^2/(1+(pz`1/pz`2)^2)+(pz`1)^2/(sqrt(1+(pz`1/pz`2)^2))^2
                              by A172,SQUARE_1:def 4
               .= (pz`2)^2/(1+(pz`1/pz`2)^2)+(pz`1)^2/(1+(pz`1/pz`2)^2)
                              by A172,SQUARE_1:def 4
               .= ((pz`2)^2+(pz`1)^2)/(1+(pz`1/pz`2)^2) by XCMPLX_1:63;
        then ((pz`2)^2+(pz`1)^2)/(1+(pz`1/pz`2)^2)*(1+(pz`1/pz`2)^2)
            <=1 *(1+(pz`1/pz`2)^2) by A172,A173,AXIOMS:25;
        then ((pz`2)^2+(pz`1)^2)<=(1+(pz`1/pz`2)^2) by A172,XCMPLX_1:88;
         then (pz`2)^2+(pz`1)^2<=1+(pz`1)^2/(pz`2)^2 by SQUARE_1:69;
         then (pz`2)^2+(pz`1)^2-1<=(pz`1)^2/(pz`2)^2 by REAL_1:86;
         then ((pz`2)^2+(pz`1)^2-1)*(pz`2)^2<=(pz`1)^2/(pz`2)^2*(pz`2)^2
                              by A171,AXIOMS:25;
         then ((pz`2)^2+(pz`1)^2-1)*(pz`2)^2<=(pz`1)^2 by A174,XCMPLX_1:88;
         then A175:((pz`2)^2-1)*((pz`2)^2+(pz`1)^2)<=0 by Lm16;
         A176: (pz`2)^2+(pz`1)^2<>0 by A165,COMPLEX1:2;
           (pz`1)^2>=0 by SQUARE_1:72;
         then (pz`2)^2+(pz`1)^2>=0+0 by A171,REAL_1:55;
         then A177: (pz`2)^2-1<=0 by A175,A176,REAL_2:122;
         then A178:pz`2<=1 & pz`2>=-1 by Th5;
         then (pz`1<=1 & --pz`2>=-pz`1 or pz`1>=-1 & pz`1<=-pz`2)
                   by A163,A167,AXIOMS:22,REAL_1:50;
         then (pz`1<=1 & 1>=-pz`1 or pz`1>=-1 & -pz`1>=--pz`2)
                   by A178,AXIOMS:22,REAL_1:50;
         then (pz`1<=1 & 1>=-pz`1 or pz`1>=-1 & -pz`1>=-1) by A178,AXIOMS:22;
         then (pz`1<=1 & -1<=--pz`1 or pz`1>=-1 & pz`1<=1) by REAL_1:50;
        hence -1<=(gg.r)`1 & (gg.r)`1<=1 & -1 <=(gg.r)`2 & (gg.r)`2<=1 by A177,
Th5;
       end;
       hence -1<=(ff.r)`1 & (ff.r)`1<=1 & -1<=(gg.r)`1 & (gg.r)`1<=1 &
        -1 <=(ff.r)`2 & (ff.r)`2<=1 & -1 <=(gg.r)`2 & (gg.r)`2<=1 by A100;
      end;
    then rng ff meets rng gg by A1,A7,A8,A9,A10,A15,JGRAPH_1:65;
    then A179:rng ff /\ rng gg <>{} by XBOOLE_0:def 7;
    consider y being Element of rng ff /\ rng gg;
    A180: y in rng ff & y in rng gg by A179,XBOOLE_0:def 3;
    then consider x1 being set such that
    A181: x1 in dom ff & y=ff.x1 by FUNCT_1:def 5;
    consider x2 being set such that
    A182: x2 in dom gg & y=gg.x2 by A180,FUNCT_1:def 5;
    A183:ff.x1=Sq_Circ".(f.x1) by A181,FUNCT_1:22;
    A184:dom (Sq_Circ")=the carrier of TOP-REAL 2 by Th39,FUNCT_2:def 1;
      x1 in dom f by A181,FUNCT_1:21;
    then A185:f.x1 in rng f by FUNCT_1:def 5;
      x2 in dom g by A182,FUNCT_1:21;
    then A186:g.x2 in rng g by FUNCT_1:def 5;
      gg.x2=Sq_Circ".(g.x2) by A182,FUNCT_1:22;
    then f.x1=g.x2 by A181,A182,A183,A184,A185,A186,Lm15,FUNCT_1:def 8;
    then rng f /\ rng g <> {} by A185,A186,XBOOLE_0:def 3;
  hence thesis by XBOOLE_0:def 7;
end;


Back to top