let a, b, d, e, s1, s2, t1, t2 be Real; :: thesis: for h being Function of (Closed-Interval-TSpace a,b),(Closed-Interval-TSpace d,e) st h is being_homeomorphism & h . s1 = t1 & h . s2 = t2 & h . a = d & h . b = e & d <= e & t1 <= t2 & s1 in [.a,b.] & s2 in [.a,b.] holds
s1 <= s2
let h be Function of (Closed-Interval-TSpace a,b),(Closed-Interval-TSpace d,e); :: thesis: ( h is being_homeomorphism & h . s1 = t1 & h . s2 = t2 & h . a = d & h . b = e & d <= e & t1 <= t2 & s1 in [.a,b.] & s2 in [.a,b.] implies s1 <= s2 )
assume A1:
( h is being_homeomorphism & h . s1 = t1 & h . s2 = t2 & h . a = d & h . b = e & d <= e & t1 <= t2 & s1 in [.a,b.] & s2 in [.a,b.] )
; :: thesis: s1 <= s2
then A2:
h is one-to-one
by TOPS_2:def 5;
A3:
( a <= s2 & s2 <= b )
by A1, XXREAL_1:1;
A4:
( a <= s1 & s1 <= b )
by A1, XXREAL_1:1;
A5: dom h =
[#] (Closed-Interval-TSpace a,b)
by A1, TOPS_2:def 5
.=
[.a,b.]
by A4, TOPMETR:25, XXREAL_0:2
;
A6:
h is continuous
by A1, TOPS_2:def 5;
A7:
the carrier of (Closed-Interval-TSpace a,b) = [.a,b.]
by A4, TOPMETR:25, XXREAL_0:2;
A8:
the carrier of (Closed-Interval-TSpace d,e) = [.d,e.]
by A1, TOPMETR:25;
A9:
h is one-to-one
by A1, TOPS_2:def 5;
reconsider B = [.s2,s1.] as Subset of (Closed-Interval-TSpace a,b) by A3, A4, A7, XXREAL_1:34;
reconsider Bb = [.s2,s1.] as Subset of (Closed-Interval-TSpace a,b) by A3, A4, A7, XXREAL_1:34;
assume A10:
s1 > s2
; :: thesis: contradiction
reconsider f3 = h | Bb as Function of ((Closed-Interval-TSpace a,b) | B),(Closed-Interval-TSpace d,e) by PRE_TOPC:30;
A11:
f3 is continuous
by A6, TOPMETR:10;
reconsider C = [.d,e.] as non empty Subset of R^1 by A1, TOPMETR:24, XXREAL_1:1;
A12:
R^1 | C = Closed-Interval-TSpace d,e
by A1, TOPMETR:26;
A13:
Closed-Interval-TSpace s2,s1 = (Closed-Interval-TSpace a,b) | B
by A3, A4, A10, TOPMETR:30;
then
f3 is Function of (Closed-Interval-TSpace s2,s1),R^1
by A12, JORDAN6:4;
then reconsider f = h | B as Function of (Closed-Interval-TSpace s2,s1),R^1 ;
dom f = the carrier of (Closed-Interval-TSpace s2,s1)
by FUNCT_2:def 1;
then A14:
dom f = [.s2,s1.]
by A10, TOPMETR:25;
A15:
f is continuous
by A11, A12, A13, JORDAN6:4;
set t = (t1 + t2) / 2;
s2 in B
by A10, XXREAL_1:1;
then A16:
f . s2 = t2
by A1, FUNCT_1:72;
s1 in B
by A10, XXREAL_1:1;
then A17:
f . s1 = t1
by A1, FUNCT_1:72;
t1 <> t2
by A1, A2, A5, A10, FUNCT_1:def 8;
then A18:
t1 < t2
by A1, XXREAL_0:1;
then
t1 + t1 < t1 + t2
by XREAL_1:10;
then A19:
(2 * t1) / 2 < (t1 + t2) / 2
by XREAL_1:76;
t1 + t2 < t2 + t2
by A18, XREAL_1:10;
then A20:
(2 * t2) / 2 > (t1 + t2) / 2
by XREAL_1:76;
then consider r being Real such that
A21:
( f . r = (t1 + t2) / 2 & s2 < r & r < s1 )
by A10, A15, A16, A17, A19, TOPREAL5:13;
A22:
r < b
by A4, A21, XXREAL_0:2;
a < r
by A3, A21, XXREAL_0:2;
then A23:
r in [.a,b.]
by A22, XXREAL_1:1;
reconsider B1 = [.s1,b.] as Subset of (Closed-Interval-TSpace a,b) by A4, A7, XXREAL_1:34;
reconsider B1b = [.s1,b.] as Subset of (Closed-Interval-TSpace a,b) by A4, A7, XXREAL_1:34;
reconsider f4 = h | B1b as Function of ((Closed-Interval-TSpace a,b) | B1),(Closed-Interval-TSpace d,e) by PRE_TOPC:30;
A24:
Closed-Interval-TSpace s1,b = (Closed-Interval-TSpace a,b) | B1
by A4, TOPMETR:30;
A25:
f4 is continuous
by A6, TOPMETR:10;
f4 is Function of (Closed-Interval-TSpace s1,b),R^1
by A12, A24, JORDAN6:4;
then reconsider f1 = h | B1 as Function of (Closed-Interval-TSpace s1,b),R^1 ;
A26:
f1 is continuous
by A12, A24, A25, JORDAN6:4;
s2 in dom f
by A10, A14, XXREAL_1:1;
then
t2 in rng f3
by A16, FUNCT_1:def 5;
then A27:
( d <= t2 & t2 <= e )
by A8, XXREAL_1:1;
then A28:
s1 < b
by A1, A4, A18, XXREAL_0:1;
A29:
s1 in B1
by A4, XXREAL_1:1;
A30:
b in B1
by A4, XXREAL_1:1;
A31:
f1 . s1 = t1
by A1, A29, FUNCT_1:72;
A32:
f1 . b = e
by A1, A30, FUNCT_1:72;
( e > (t1 + t2) / 2 & (t1 + t2) / 2 > t1 )
by A19, A20, A27, XXREAL_0:2;
then consider r1 being Real such that
A33:
( f1 . r1 = (t1 + t2) / 2 & s1 < r1 & r1 < b )
by A26, A28, A31, A32, TOPREAL5:12;
a < r1
by A4, A33, XXREAL_0:2;
then A34:
r1 in [.a,b.]
by A33, XXREAL_1:1;
A35:
r1 in B1
by A33, XXREAL_1:1;
r in [.s2,s1.]
by A21, XXREAL_1:1;
then h . r =
(t1 + t2) / 2
by A21, FUNCT_1:72
.=
h . r1
by A33, A35, FUNCT_1:72
;
hence
contradiction
by A5, A9, A21, A23, A33, A34, FUNCT_1:def 8; :: thesis: verum