let o, p be Point of (TOP-REAL 2); :: thesis: for r being positive real number st p is Point of (Tdisk o,r) holds
DiskProj o,r,p is continuous

let r be positive real number ; :: thesis: ( p is Point of (Tdisk o,r) implies DiskProj o,r,p is continuous )
assume A1: p is Point of (Tdisk o,r) ; :: thesis: DiskProj o,r,p is continuous
set D = Tdisk o,r;
set cB = cl_Ball o,r;
set Bp = (cl_Ball o,r) \ {p};
set OK = [:((cl_Ball o,r) \ {p}),{p}:];
set D1 = (TOP-REAL 2) | ((cl_Ball o,r) \ {p});
set D2 = (TOP-REAL 2) | {p};
set S1 = Tcircle o,r;
A2: p in {p} by TARSKI:def 1;
A3: the carrier of (Tdisk o,r) = cl_Ball o,r by BROUWER:3;
A4: the carrier of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) = (cl_Ball o,r) \ {p} by PRE_TOPC:29;
A5: the carrier of ((TOP-REAL 2) | {p}) = {p} by PRE_TOPC:29;
set TD = [:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:];
set gg = DiskProj o,r,p;
set xo = diffX2_1 o;
set yo = diffX2_2 o;
set dx = diffX1_X2_1 ;
set dy = diffX1_X2_2 ;
set fx2 = Proj2_1 ;
set fy2 = Proj2_2 ;
reconsider rr = r ^2 as Real by XREAL_0:def 1;
set f1 = the carrier of [:(TOP-REAL 2),(TOP-REAL 2):] --> rr;
reconsider f1 = the carrier of [:(TOP-REAL 2),(TOP-REAL 2):] --> rr as continuous RealMap of [:(TOP-REAL 2),(TOP-REAL 2):] by Lm8;
set Zf1 = f1 | [:((cl_Ball o,r) \ {p}),{p}:];
set Zfx2 = Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:];
set Zfy2 = Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:];
set Zdx = diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:];
set Zdy = diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:];
set Zxo = (diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:];
set Zyo = (diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:];
set xx = ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]);
set yy = ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]);
set m = ((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]));
A6: the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) = [:((cl_Ball o,r) \ {p}),{p}:] by PRE_TOPC:29;
A7: for y being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for z being Point of ((TOP-REAL 2) | {p}) holds (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_1 . [y,z]
proof
let y be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for z being Point of ((TOP-REAL 2) | {p}) holds (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_1 . [y,z]
let z be Point of ((TOP-REAL 2) | {p}); :: thesis: (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_1 . [y,z]
[y,z] in [:((cl_Ball o,r) \ {p}),{p}:] by A4, A5, ZFMISC_1:def 2;
hence (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_1 . [y,z] by FUNCT_1:72; :: thesis: verum
end;
A8: for y being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for z being Point of ((TOP-REAL 2) | {p}) holds (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_2 . [y,z]
proof
let y be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for z being Point of ((TOP-REAL 2) | {p}) holds (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_2 . [y,z]
let z be Point of ((TOP-REAL 2) | {p}); :: thesis: (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_2 . [y,z]
[y,z] in [:((cl_Ball o,r) \ {p}),{p}:] by A4, A5, ZFMISC_1:def 2;
hence (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_2 . [y,z] by FUNCT_1:72; :: thesis: verum
end;
A9: for y being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for z being Point of ((TOP-REAL 2) | {p}) holds (Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_1 . [y,z]
proof
let y be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for z being Point of ((TOP-REAL 2) | {p}) holds (Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_1 . [y,z]
let z be Point of ((TOP-REAL 2) | {p}); :: thesis: (Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_1 . [y,z]
[y,z] in [:((cl_Ball o,r) \ {p}),{p}:] by A4, A5, ZFMISC_1:def 2;
hence (Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_1 . [y,z] by FUNCT_1:72; :: thesis: verum
end;
A10: for y being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for z being Point of ((TOP-REAL 2) | {p}) holds (Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_2 . [y,z]
proof
let y be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for z being Point of ((TOP-REAL 2) | {p}) holds (Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_2 . [y,z]
let z be Point of ((TOP-REAL 2) | {p}); :: thesis: (Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_2 . [y,z]
[y,z] in [:((cl_Ball o,r) \ {p}),{p}:] by A4, A5, ZFMISC_1:def 2;
hence (Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = Proj2_2 . [y,z] by FUNCT_1:72; :: thesis: verum
end;
A11: for y being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for z being Point of ((TOP-REAL 2) | {p}) holds (f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = f1 . [y,z]
proof
let y be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for z being Point of ((TOP-REAL 2) | {p}) holds (f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = f1 . [y,z]
let z be Point of ((TOP-REAL 2) | {p}); :: thesis: (f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = f1 . [y,z]
[y,z] in [:((cl_Ball o,r) \ {p}),{p}:] by A4, A5, ZFMISC_1:def 2;
hence (f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = f1 . [y,z] by FUNCT_1:72; :: thesis: verum
end;
A12: for y being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for z being Point of ((TOP-REAL 2) | {p}) holds ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_1 o) . [y,z]
proof
let y be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for z being Point of ((TOP-REAL 2) | {p}) holds ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_1 o) . [y,z]
let z be Point of ((TOP-REAL 2) | {p}); :: thesis: ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_1 o) . [y,z]
[y,z] in [:((cl_Ball o,r) \ {p}),{p}:] by A4, A5, ZFMISC_1:def 2;
hence ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_1 o) . [y,z] by FUNCT_1:72; :: thesis: verum
end;
A13: for y being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for z being Point of ((TOP-REAL 2) | {p}) holds ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_2 o) . [y,z]
proof
let y be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for z being Point of ((TOP-REAL 2) | {p}) holds ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_2 o) . [y,z]
let z be Point of ((TOP-REAL 2) | {p}); :: thesis: ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_2 o) . [y,z]
[y,z] in [:((cl_Ball o,r) \ {p}),{p}:] by A4, A5, ZFMISC_1:def 2;
hence ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_2 o) . [y,z] by FUNCT_1:72; :: thesis: verum
end;
now
let b be real number ; :: thesis: ( b in rng (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) implies 0 < b )
assume b in rng (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) ; :: thesis: 0 < b
then consider a being set such that
A14: a in dom (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) and
A15: (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) . a = b by FUNCT_1:def 5;
consider y, z being set such that
A16: ( y in (cl_Ball o,r) \ {p} & z in {p} & a = [y,z] ) by A6, A14, ZFMISC_1:def 2;
A17: z = p by A16, TARSKI:def 1;
reconsider y = y, z = z as Point of (TOP-REAL 2) by A16;
A18: y <> z by A16, A17, ZFMISC_1:64;
[y,z] = [([y,z] `1 ),([y,z] `2 )] by Lm7, MCART_1:23;
then A19: ( y = [y,z] `1 & z = [y,z] `2 ) by ZFMISC_1:33;
A20: diffX1_X2_1 . [y,z] = (([y,z] `1 ) `1 ) - (([y,z] `2 ) `1 ) by Def3;
A21: diffX1_X2_2 . [y,z] = (([y,z] `1 ) `2 ) - (([y,z] `2 ) `2 ) by Def4;
set r1 = (y `1 ) - (z `1 );
set r2 = (y `2 ) - (z `2 );
A22: (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_1 . [y,z] by A4, A5, A7, A16;
A23: (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = diffX1_X2_2 . [y,z] by A4, A5, A8, A16;
A24: (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) . [y,z] = (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,z]) + (((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,z]) by A14, A16, VALUED_1:1
.= (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z]) * ((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z])) + (((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,z]) by VALUED_1:5
.= (((y `1 ) - (z `1 )) ^2 ) + (((y `2 ) - (z `2 )) ^2 ) by A19, A20, A21, A22, A23, VALUED_1:5 ;
now
assume (((y `1 ) - (z `1 )) ^2 ) + (((y `2 ) - (z `2 )) ^2 ) = 0 ; :: thesis: contradiction
then ( (y `1 ) - (z `1 ) = 0 & (y `2 ) - (z `2 ) = 0 ) by COMPLEX1:2;
hence contradiction by A18, TOPREAL3:11; :: thesis: verum
end;
hence 0 < b by A15, A16, A24; :: thesis: verum
end;
then reconsider m = ((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) as continuous positive-yielding RealMap of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by PARTFUN3:def 1;
set p1 = ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])));
set p2 = ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:]);
A26: dom (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:])) = the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by FUNCT_2:def 1;
now
let b be real number ; :: thesis: ( b in rng (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:])) implies 0 >= b )
assume b in rng (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:])) ; :: thesis: 0 >= b
then consider a being set such that
A27: a in dom (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:])) and
A28: (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:])) . a = b by FUNCT_1:def 5;
consider y, z being set such that
A29: ( y in (cl_Ball o,r) \ {p} & z in {p} & a = [y,z] ) by A6, A27, ZFMISC_1:def 2;
reconsider y = y, z = z as Point of (TOP-REAL 2) by A29;
set r3 = (z `1 ) - (o `1 );
set r4 = (z `2 ) - (o `2 );
A30: (f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = f1 . [y,z] by A4, A5, A11, A29;
A31: ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_1 o) . [y,z] by A4, A5, A12, A29;
A32: ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z] = (diffX2_2 o) . [y,z] by A4, A5, A13, A29;
A33: [y,z] = [([y,z] `1 ),([y,z] `2 )] by Lm7, MCART_1:23;
A34: (diffX2_1 o) . [y,z] = (([y,z] `2 ) `1 ) - (o `1 ) by Def1;
A35: ( y = [y,z] `1 & z = [y,z] `2 ) by A33, ZFMISC_1:33;
A36: (diffX2_2 o) . [y,z] = (([y,z] `2 ) `2 ) - (o `2 ) by Def2;
A37: (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,z] = (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) . [y,z]) - ((f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z]) by A27, A29, VALUED_1:13
.= (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) . [y,z]) - (r ^2 ) by A30, FUNCOP_1:13
.= (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,z]) + ((((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,z])) - (r ^2 ) by A27, A29, VALUED_1:1
.= (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z]) * (((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,z])) + ((((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,z])) - (r ^2 ) by VALUED_1:5
.= ((((z `1 ) - (o `1 )) ^2 ) + (((z `2 ) - (o `2 )) ^2 )) - (r ^2 ) by A31, A32, A34, A35, A36, VALUED_1:5 ;
z = p by A29, TARSKI:def 1;
then |.(z - o).| <= r by A1, A3, TOPREAL9:8;
then A38: |.(z - o).| ^2 <= r ^2 by SQUARE_1:77;
|.(z - o).| ^2 = (((z - o) `1 ) ^2 ) + (((z - o) `2 ) ^2 ) by JGRAPH_1:46
.= (((z `1 ) - (o `1 )) ^2 ) + (((z - o) `2 ) ^2 ) by TOPREAL3:8
.= (((z `1 ) - (o `1 )) ^2 ) + (((z `2 ) - (o `2 )) ^2 ) by TOPREAL3:8 ;
then ((((z `1 ) - (o `1 )) ^2 ) + (((z `2 ) - (o `2 )) ^2 )) - (r ^2 ) <= (r ^2 ) - (r ^2 ) by A38, XREAL_1:11;
hence 0 >= b by A28, A29, A37; :: thesis: verum
end;
then reconsider p2 = ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) - (f1 | [:((cl_Ball o,r) \ {p}),{p}:]) as continuous nonpositive-yielding RealMap of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by PARTFUN3:def 3;
set pp = (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2);
set k = ((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m;
set x3 = (Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) + ((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]));
set y3 = (Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) + ((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]));
reconsider X3 = (Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) + ((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])), Y3 = (Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) + ((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) as Function of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]),R^1 by TOPMETR:24;
set F = <:X3,Y3:>;
set R = R2Homeomorphism ;
A39: for x being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) holds (DiskProj o,r,p) . x = (R2Homeomorphism * <:X3,Y3:>) . [x,p]
proof
let x be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: (DiskProj o,r,p) . x = (R2Homeomorphism * <:X3,Y3:>) . [x,p]
consider y being Point of (TOP-REAL 2) such that
A40: ( x = y & (DiskProj o,r,p) . x = HC p,y,o,r ) by A1, Def7;
A41: x <> p by A4, ZFMISC_1:64;
A42: [y,p] in [:((cl_Ball o,r) \ {p}),{p}:] by A2, A4, A40, ZFMISC_1:def 2;
set r1 = (y `1 ) - (p `1 );
set r2 = (y `2 ) - (p `2 );
set r3 = (p `1 ) - (o `1 );
set r4 = (p `2 ) - (o `2 );
set l = ((- ((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 ))))) + (sqrt ((((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 ) - (((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) * (((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 )))))) / ((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 ));
[y,p] = [([y,p] `1 ),([y,p] `2 )] by Lm7, MCART_1:23;
then A43: ( y = [y,p] `1 & p = [y,p] `2 ) by ZFMISC_1:33;
A44: Proj2_1 . [y,p] = ([y,p] `2 ) `1 by Def5;
A45: Proj2_2 . [y,p] = ([y,p] `2 ) `2 by Def6;
A46: diffX1_X2_1 . [y,p] = (([y,p] `1 ) `1 ) - (([y,p] `2 ) `1 ) by Def3;
A47: diffX1_X2_2 . [y,p] = (([y,p] `1 ) `2 ) - (([y,p] `2 ) `2 ) by Def4;
A48: (diffX2_1 o) . [y,p] = (([y,p] `2 ) `1 ) - (o `1 ) by Def1;
A49: (diffX2_2 o) . [y,p] = (([y,p] `2 ) `2 ) - (o `2 ) by Def2;
A50: dom X3 = the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by FUNCT_2:def 1;
A51: dom Y3 = the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by FUNCT_2:def 1;
A52: dom ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)) = the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by FUNCT_2:def 1;
A53: ( y is Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) & p is Point of ((TOP-REAL 2) | {p}) ) by A5, A40, TARSKI:def 1;
then A54: (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p] = diffX1_X2_1 . [y,p] by A7;
A55: (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p] = diffX1_X2_2 . [y,p] by A8, A53;
A56: (f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p] = f1 . [y,p] by A11, A53;
A57: ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p] = (diffX2_1 o) . [y,p] by A12, A53;
A58: ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p] = (diffX2_2 o) . [y,p] by A13, A53;
A59: m . [y,p] = (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) + (((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) by A6, A42, VALUED_1:1
.= (((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) * ((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p])) + (((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) by VALUED_1:5
.= (((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 ) by A43, A46, A47, A54, A55, VALUED_1:5 ;
A60: (((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p] = (((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) * ((diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) by VALUED_1:5;
A61: (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p] = (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) * ((diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) by VALUED_1:5;
A62: ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) . [y,p] = ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) + ((((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) by A6, A42, VALUED_1:1;
then A63: (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) . [y,p] = ((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 by A43, A46, A47, A48, A49, A54, A55, A57, A58, A60, A61, VALUED_1:5;
A64: p2 . [y,p] = (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) . [y,p]) - ((f1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) by A6, A26, A42, VALUED_1:13
.= (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]))) . [y,p]) - (r ^2 ) by A56, FUNCOP_1:13
.= (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) + ((((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p])) - (r ^2 ) by A6, A42, VALUED_1:1
.= (((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) * (((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p])) + ((((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) ((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p])) - (r ^2 ) by VALUED_1:5
.= ((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 ) by A43, A48, A49, A57, A58, VALUED_1:5 ;
dom (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2))) = the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by FUNCT_2:def 1;
then A65: (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2))) . [y,p] = sqrt (((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)) . [y,p]) by A6, A42, PARTFUN3:def 5
.= sqrt (((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) . [y,p]) - ((m (#) p2) . [y,p])) by A6, A42, A52, VALUED_1:13
.= sqrt ((((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 ) - (((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) * (((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 )))) by A59, A63, A64, VALUED_1:5 ;
dom (((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) = the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by FUNCT_2:def 1;
then A66: (((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) . [y,p] = (((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) . [y,p]) * ((m . [y,p]) " ) by A6, A42, RFUNCT_1:def 4
.= (((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) . [y,p]) / (m . [y,p]) by XCMPLX_0:def 9
.= (((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) . [y,p]) + ((sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2))) . [y,p])) / ((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) by A6, A42, A59, VALUED_1:1
.= ((- ((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 ))))) + (sqrt ((((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 ) - (((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) * (((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 )))))) / ((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) by A43, A46, A47, A48, A49, A54, A55, A57, A58, A60, A61, A62, A65, VALUED_1:8 ;
A67: X3 . [y,p] = ((Proj2_1 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) + (((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) by A6, A42, VALUED_1:1
.= (p `1 ) + (((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) by A9, A43, A44, A53
.= (p `1 ) + ((((- ((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 ))))) + (sqrt ((((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 ) - (((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) * (((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 )))))) / ((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 ))) * ((y `1 ) - (p `1 ))) by A43, A46, A54, A66, VALUED_1:5 ;
A68: Y3 . [y,p] = ((Proj2_2 | [:((cl_Ball o,r) \ {p}),{p}:]) . [y,p]) + (((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) by A6, A42, VALUED_1:1
.= (p `2 ) + (((((- ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) + (sqrt ((((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:]))) (#) ((((diffX2_1 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_1 | [:((cl_Ball o,r) \ {p}),{p}:])) + (((diffX2_2 o) | [:((cl_Ball o,r) \ {p}),{p}:]) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])))) - (m (#) p2)))) / m) (#) (diffX1_X2_2 | [:((cl_Ball o,r) \ {p}),{p}:])) . [y,p]) by A10, A43, A45, A53
.= (p `2 ) + ((((- ((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 ))))) + (sqrt ((((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 ) - (((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) * (((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 )))))) / ((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 ))) * ((y `2 ) - (p `2 ))) by A43, A47, A55, A66, VALUED_1:5 ;
A69: y in (cl_Ball o,r) \ {p} by A4, A40;
(cl_Ball o,r) \ {p} c= cl_Ball o,r by XBOOLE_1:36;
hence (DiskProj o,r,p) . x = |[((p `1 ) + ((((- ((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 ))))) + (sqrt ((((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 ) - (((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) * (((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 )))))) / ((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 ))) * ((y `1 ) - (p `1 )))),((p `2 ) + ((((- ((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 ))))) + (sqrt ((((((p `1 ) - (o `1 )) * ((y `1 ) - (p `1 ))) + (((p `2 ) - (o `2 )) * ((y `2 ) - (p `2 )))) ^2 ) - (((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 )) * (((((p `1 ) - (o `1 )) ^2 ) + (((p `2 ) - (o `2 )) ^2 )) - (r ^2 )))))) / ((((y `1 ) - (p `1 )) ^2 ) + (((y `2 ) - (p `2 )) ^2 ))) * ((y `2 ) - (p `2 ))))]| by A1, A3, A40, A41, A69, BROUWER:8
.= R2Homeomorphism . [(X3 . [y,p]),(Y3 . [y,p])] by A67, A68, TOPREALA:def 2
.= R2Homeomorphism . (<:X3,Y3:> . [y,p]) by A6, A42, A50, A51, FUNCT_3:69
.= (R2Homeomorphism * <:X3,Y3:>) . [x,p] by A6, A40, A42, FUNCT_2:21 ;
:: thesis: verum
end;
( X3 is continuous & Y3 is continuous ) by TOPREAL6:83;
then reconsider F = <:X3,Y3:> as continuous Function of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]),[:R^1 ,R^1 :] by YELLOW12:41;
for pp being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))
for V being Subset of (Tcircle o,r) st (DiskProj o,r,p) . pp in V & V is open holds
ex W being Subset of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) st
( pp in W & W is open & (DiskProj o,r,p) .: W c= V )
proof
let pp be Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})); :: thesis: for V being Subset of (Tcircle o,r) st (DiskProj o,r,p) . pp in V & V is open holds
ex W being Subset of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) st
( pp in W & W is open & (DiskProj o,r,p) .: W c= V )

let V be Subset of (Tcircle o,r); :: thesis: ( (DiskProj o,r,p) . pp in V & V is open implies ex W being Subset of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) st
( pp in W & W is open & (DiskProj o,r,p) .: W c= V ) )

assume that
A70: (DiskProj o,r,p) . pp in V and
A71: V is open ; :: thesis: ex W being Subset of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) st
( pp in W & W is open & (DiskProj o,r,p) .: W c= V )

reconsider p1 = pp, fp = p as Point of (TOP-REAL 2) by PRE_TOPC:55;
A72: [pp,p] in [:((cl_Ball o,r) \ {p}),{p}:] by A2, A4, ZFMISC_1:def 2;
consider V1 being Subset of (TOP-REAL 2) such that
A73: V1 is open and
A74: V1 /\ ([#] (Tcircle o,r)) = V by A71, TOPS_2:32;
A75: (DiskProj o,r,p) . pp = (R2Homeomorphism * F) . [pp,p] by A39;
R2Homeomorphism " is being_homeomorphism by TOPREALA:56, TOPS_2:70;
then A76: (R2Homeomorphism " ) .: V1 is open by A73, TOPGRP_1:25;
A77: dom F = the carrier of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) by FUNCT_2:def 1;
A78: dom R2Homeomorphism = the carrier of [:R^1 ,R^1 :] by FUNCT_2:def 1;
then A79: rng F c= dom R2Homeomorphism ;
then A80: dom (R2Homeomorphism * F) = dom F by RELAT_1:46;
A81: ( rng R2Homeomorphism = [#] (TOP-REAL 2) & R2Homeomorphism is one-to-one ) by TOPREALA:56, TOPS_2:def 5;
A82: (R2Homeomorphism " ) * (R2Homeomorphism * F) = ((R2Homeomorphism " ) * R2Homeomorphism ) * F by RELAT_1:55
.= (id (dom R2Homeomorphism )) * F by A81, TOPS_2:65 ;
dom (id (dom R2Homeomorphism )) = dom R2Homeomorphism by RELAT_1:71;
then A83: dom ((id (dom R2Homeomorphism )) * F) = dom F by A79, RELAT_1:46;
for x being set st x in dom F holds
((id (dom R2Homeomorphism )) * F) . x = F . x
proof
let x be set ; :: thesis: ( x in dom F implies ((id (dom R2Homeomorphism )) * F) . x = F . x )
assume A84: x in dom F ; :: thesis: ((id (dom R2Homeomorphism )) * F) . x = F . x
A85: F . x in rng F by A84, FUNCT_1:def 5;
thus ((id (dom R2Homeomorphism )) * F) . x = (id (dom R2Homeomorphism )) . (F . x) by A84, FUNCT_1:23
.= F . x by A78, A85, FUNCT_1:35 ; :: thesis: verum
end;
then A86: (id (dom R2Homeomorphism )) * F = F by A83, FUNCT_1:9;
(R2Homeomorphism * F) . [p1,fp] in V1 by A70, A74, A75, XBOOLE_0:def 4;
then (R2Homeomorphism " ) . ((R2Homeomorphism * F) . [p1,fp]) in (R2Homeomorphism " ) .: V1 by FUNCT_2:43;
then ((R2Homeomorphism " ) * (R2Homeomorphism * F)) . [p1,fp] in (R2Homeomorphism " ) .: V1 by A6, A72, A77, A80, FUNCT_1:23;
then consider W being Subset of ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]) such that
A87: [p1,fp] in W and
A88: W is open and
A89: F .: W c= (R2Homeomorphism " ) .: V1 by A6, A72, A76, A82, A86, JGRAPH_2:20;
consider WW being Subset of [:(TOP-REAL 2),(TOP-REAL 2):] such that
A90: WW is open and
A91: WW /\ ([#] ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:])) = W by A88, TOPS_2:32;
consider SF being Subset-Family of [:(TOP-REAL 2),(TOP-REAL 2):] such that
A92: WW = union SF and
A93: for e being set st e in SF holds
ex X1, Y1 being Subset of (TOP-REAL 2) st
( e = [:X1,Y1:] & X1 is open & Y1 is open ) by A90, BORSUK_1:45;
[p1,fp] in WW by A87, A91, XBOOLE_0:def 4;
then consider Z being set such that
A94: [p1,fp] in Z and
A95: Z in SF by A92, TARSKI:def 4;
consider X1, Y1 being Subset of (TOP-REAL 2) such that
A96: Z = [:X1,Y1:] and
A97: X1 is open and
Y1 is open by A93, A95;
set ZZ = Z /\ ([#] ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]));
reconsider XX = X1 /\ ([#] ((TOP-REAL 2) | ((cl_Ball o,r) \ {p}))) as open Subset of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) by A97, TOPS_2:32;
take XX ; :: thesis: ( pp in XX & XX is open & (DiskProj o,r,p) .: XX c= V )
pp in X1 by A94, A96, ZFMISC_1:106;
hence pp in XX by XBOOLE_0:def 4; :: thesis: ( XX is open & (DiskProj o,r,p) .: XX c= V )
thus XX is open ; :: thesis: (DiskProj o,r,p) .: XX c= V
let b be set ; :: according to TARSKI:def 3 :: thesis: ( not b in (DiskProj o,r,p) .: XX or b in V )
assume b in (DiskProj o,r,p) .: XX ; :: thesis: b in V
then consider a being Point of ((TOP-REAL 2) | ((cl_Ball o,r) \ {p})) such that
A98: a in XX and
A99: b = (DiskProj o,r,p) . a by FUNCT_2:116;
reconsider a1 = a, fa = fp as Point of (TOP-REAL 2) by PRE_TOPC:55;
A100: a in X1 by A98, XBOOLE_0:def 4;
A101: [a,p] in [:((cl_Ball o,r) \ {p}),{p}:] by A2, A4, ZFMISC_1:def 2;
fa in Y1 by A94, A96, ZFMISC_1:106;
then [a,fa] in Z by A96, A100, ZFMISC_1:def 2;
then [a,fa] in Z /\ ([#] ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:])) by A6, A101, XBOOLE_0:def 4;
then A102: F . [a1,fa] in F .: (Z /\ ([#] ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]))) by FUNCT_2:43;
A103: R2Homeomorphism " = R2Homeomorphism " by A81, TOPS_2:def 4;
A104: dom (R2Homeomorphism " ) = [#] (TOP-REAL 2) by A81, TOPS_2:62;
Z c= WW by A92, A95, ZFMISC_1:92;
then Z /\ ([#] ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:])) c= WW /\ ([#] ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:])) by XBOOLE_1:27;
then F .: (Z /\ ([#] ([:(TOP-REAL 2),(TOP-REAL 2):] | [:((cl_Ball o,r) \ {p}),{p}:]))) c= F .: W by A91, RELAT_1:156;
then F . [a1,fa] in F .: W by A102;
then R2Homeomorphism . (F . [a1,fa]) in R2Homeomorphism .: ((R2Homeomorphism " ) .: V1) by A89, FUNCT_2:43;
then (R2Homeomorphism * F) . [a1,fa] in R2Homeomorphism .: ((R2Homeomorphism " ) .: V1) by A6, A101, FUNCT_2:21;
then (R2Homeomorphism * F) . [a1,fa] in V1 by A81, A103, A104, PARTFUN3:1;
then (DiskProj o,r,p) . a in V1 by A39;
hence b in V by A74, A99, XBOOLE_0:def 4; :: thesis: verum
end;
hence DiskProj o,r,p is continuous by JGRAPH_2:20; :: thesis: verum