let P be Subset of (TOP-REAL 2); :: thesis: for p1, p2, q1, q2 being Point of (TOP-REAL 2)
for g being Function of I[01] ,((TOP-REAL 2) | P)
for s1, s2 being Real st P is_an_arc_of p1,p2 & g is being_homeomorphism & g . 0 = p1 & g . 1 = p2 & g . s1 = q1 & 0 <= s1 & s1 <= 1 & g . s2 = q2 & 0 <= s2 & s2 <= 1 & s1 <= s2 holds
LE q1,q2,P,p1,p2

let p1, p2, q1, q2 be Point of (TOP-REAL 2); :: thesis: for g being Function of I[01] ,((TOP-REAL 2) | P)
for s1, s2 being Real st P is_an_arc_of p1,p2 & g is being_homeomorphism & g . 0 = p1 & g . 1 = p2 & g . s1 = q1 & 0 <= s1 & s1 <= 1 & g . s2 = q2 & 0 <= s2 & s2 <= 1 & s1 <= s2 holds
LE q1,q2,P,p1,p2

let g be Function of I[01] ,((TOP-REAL 2) | P); :: thesis: for s1, s2 being Real st P is_an_arc_of p1,p2 & g is being_homeomorphism & g . 0 = p1 & g . 1 = p2 & g . s1 = q1 & 0 <= s1 & s1 <= 1 & g . s2 = q2 & 0 <= s2 & s2 <= 1 & s1 <= s2 holds
LE q1,q2,P,p1,p2

let s1, s2 be Real; :: thesis: ( P is_an_arc_of p1,p2 & g is being_homeomorphism & g . 0 = p1 & g . 1 = p2 & g . s1 = q1 & 0 <= s1 & s1 <= 1 & g . s2 = q2 & 0 <= s2 & s2 <= 1 & s1 <= s2 implies LE q1,q2,P,p1,p2 )
assume that
A1: P is_an_arc_of p1,p2 and
A2: g is being_homeomorphism and
A3: g . 0 = p1 and
A4: g . 1 = p2 and
A5: g . s1 = q1 and
A6: ( 0 <= s1 & s1 <= 1 ) and
A7: g . s2 = q2 and
A8: ( 0 <= s2 & s2 <= 1 ) and
A9: s1 <= s2 ; :: thesis: LE q1,q2,P,p1,p2
reconsider P9 = P as non empty Subset of (TOP-REAL 2) by A1, TOPREAL1:4;
A10: s1 in the carrier of I[01] by A6, BORSUK_1:86;
then A11: q1 in [#] ((TOP-REAL 2) | P9) by A5, FUNCT_2:7;
reconsider g = g as Function of I[01] ,((TOP-REAL 2) | P9) ;
A12: s2 in the carrier of I[01] by A8, BORSUK_1:86;
then g . s2 in the carrier of ((TOP-REAL 2) | P9) by FUNCT_2:7;
then A13: q2 in P by A7, A11, PRE_TOPC:def 10;
A14: now
reconsider s19 = s1, s29 = s2 as Point of I[01] by A6, A8, BORSUK_1:86;
let h be Function of I[01] ,((TOP-REAL 2) | P9); :: thesis: for t1, t2 being Real st h is being_homeomorphism & h . 0 = p1 & h . 1 = p2 & h . t1 = q1 & 0 <= t1 & t1 <= 1 & h . t2 = q2 & 0 <= t2 & t2 <= 1 holds
b4 <= b5

let t1, t2 be Real; :: thesis: ( h is being_homeomorphism & h . 0 = p1 & h . 1 = p2 & h . t1 = q1 & 0 <= t1 & t1 <= 1 & h . t2 = q2 & 0 <= t2 & t2 <= 1 implies b2 <= b3 )
assume that
A15: h is being_homeomorphism and
A16: h . 0 = p1 and
A17: h . 1 = p2 and
A18: h . t1 = q1 and
A19: ( 0 <= t1 & t1 <= 1 ) and
A20: h . t2 = q2 and
A21: ( 0 <= t2 & t2 <= 1 ) ; :: thesis: b2 <= b3
A22: h is one-to-one by A15, TOPS_2:def 5;
set hg = (h " ) * g;
h " is being_homeomorphism by A15, TOPS_2:70;
then (h " ) * g is being_homeomorphism by A2, TOPS_2:71;
then A23: ( (h " ) * g is continuous & (h " ) * g is one-to-one ) by TOPS_2:def 5;
( ((h " ) * g) . s1 in the carrier of I[01] & ((h " ) * g) . s2 in the carrier of I[01] ) by A10, A12, FUNCT_2:7;
then reconsider hg1 = ((h " ) * g) . s19, hg2 = ((h " ) * g) . s29 as Real by BORSUK_1:83;
A24: dom g = [#] I[01] by A2, TOPS_2:def 5;
then A25: 0 in dom g by BORSUK_1:86;
A26: dom h = [#] I[01] by A15, TOPS_2:def 5;
then A27: t1 in dom h by A19, BORSUK_1:86;
A28: 0 in dom h by A26, BORSUK_1:86;
A29: rng h = [#] ((TOP-REAL 2) | P) by A15, TOPS_2:def 5;
then (h " ) . p1 = (h " ) . p1 by A22, TOPS_2:def 4
.= 0 by A16, A28, A22, FUNCT_1:54 ;
then A30: ((h " ) * g) . 0 = 0 by A3, A25, FUNCT_1:23;
s1 in dom g by A6, A24, BORSUK_1:86;
then A31: ((h " ) * g) . s1 = (h " ) . q1 by A5, FUNCT_1:23
.= (h " ) . q1 by A29, A22, TOPS_2:def 4
.= t1 by A18, A22, A27, FUNCT_1:54 ;
A32: t2 in dom h by A21, A26, BORSUK_1:86;
s2 in dom g by A8, A24, BORSUK_1:86;
then A33: ((h " ) * g) . s2 = (h " ) . q2 by A7, FUNCT_1:23
.= (h " ) . q2 by A29, A22, TOPS_2:def 4
.= t2 by A20, A22, A32, FUNCT_1:54 ;
A34: 1 in dom g by A24, BORSUK_1:86;
A35: 1 in dom h by A26, BORSUK_1:86;
(h " ) . p2 = (h " ) . p2 by A29, A22, TOPS_2:def 4
.= 1 by A17, A35, A22, FUNCT_1:54 ;
then A36: ((h " ) * g) . 1 = 1 by A4, A34, FUNCT_1:23;
per cases ( s1 < s2 or s1 = s2 ) by A9, XXREAL_0:1;
suppose s1 = s2 ; :: thesis: b2 <= b3
hence t1 <= t2 by A31, A33; :: thesis: verum
end;
end;
end;
q1 in P by A11, PRE_TOPC:def 10;
hence LE q1,q2,P,p1,p2 by A13, A14, Def3; :: thesis: verum