let a, b, r, s be Real; :: thesis: ( a <= b & r <= s implies R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):] is Function of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):],(Trectangle (a,b,r,s)) )
set C1 = Closed-Interval-TSpace (a,b);
set C2 = Closed-Interval-TSpace (r,s);
set TR = Trectangle (a,b,r,s);
set h = R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):];
assume ( a <= b & r <= s ) ; :: thesis: R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):] is Function of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):],(Trectangle (a,b,r,s))
then A1: the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):] = [:[.a,b.],[.r,s.]:] by Th27;
dom R2Homeomorphism = [: the carrier of R^1, the carrier of R^1:] by Lm1, FUNCT_2:def 1;
then A2: dom (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) = the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):] by A1, RELAT_1:62, TOPMETR:17, ZFMISC_1:96;
rng (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) c= the carrier of (Trectangle (a,b,r,s))
proof
let y be object ; :: according to TARSKI:def 3 :: thesis: ( not y in rng (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) or y in the carrier of (Trectangle (a,b,r,s)) )
A3: ( the carrier of (Trectangle (a,b,r,s)) = closed_inside_of_rectangle (a,b,r,s) & closed_inside_of_rectangle (a,b,r,s) = { p where p is Point of (TOP-REAL 2) : ( a <= p `1 & p `1 <= b & r <= p `2 & p `2 <= s ) } ) by JGRAPH_6:def 2, PRE_TOPC:8;
assume y in rng (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) ; :: thesis: y in the carrier of (Trectangle (a,b,r,s))
then consider x being object such that
A4: x in dom (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) and
A5: (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) . x = y by FUNCT_1:def 3;
reconsider x = x as Point of [:R^1,R^1:] by A4;
dom (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) c= [: the carrier of R^1, the carrier of R^1:] by A1, A2, TOPMETR:17, ZFMISC_1:96;
then consider x1, x2 being Element of the carrier of R^1 such that
A6: x = [x1,x2] by A4, DOMAIN_1:1;
A7: x2 in [.r,s.] by A1, A2, A4, A6, ZFMISC_1:87;
A8: (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) . x = R2Homeomorphism . x by A4, FUNCT_1:47;
then reconsider p = (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) . x as Point of (TOP-REAL 2) ;
A9: (R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):]) . x = <*x1,x2*> by A8, A6, Def2;
then x2 = p `2 ;
then A10: ( r <= p `2 & p `2 <= s ) by A7, XXREAL_1:1;
A11: x1 in [.a,b.] by A1, A2, A4, A6, ZFMISC_1:87;
x1 = p `1 by A9;
then ( a <= p `1 & p `1 <= b ) by A11, XXREAL_1:1;
hence y in the carrier of (Trectangle (a,b,r,s)) by A5, A3, A10; :: thesis: verum
end;
hence R2Homeomorphism | the carrier of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):] is Function of [:(Closed-Interval-TSpace (a,b)),(Closed-Interval-TSpace (r,s)):],(Trectangle (a,b,r,s)) by A2, FUNCT_2:2; :: thesis: verum