id the carrier of I[01] = id I[01]
;
then reconsider fA = id the carrier of I[01] as continuous Function of I[01] ,I[01] ;
set LL = L[01] (0 ,1 (#) ),((#) 0 ,1);
reconsider fB = L[01] (0 ,1 (#) ),((#) 0 ,1) as continuous Function of I[01] ,I[01] by TOPMETR:27, TREAL_1:11;
let P, Q be Path of a,b; ( ex f being Function of [:I[01] ,I[01] :],T st
( f is continuous & ( for t being Point of I[01] holds
( f . t,0 = P . t & f . t,1 = Q . t & f . 0 ,t = a & f . 1,t = b ) ) ) implies ex f being Function of [:I[01] ,I[01] :],T st
( f is continuous & ( for t being Point of I[01] holds
( f . t,0 = Q . t & f . t,1 = P . t & f . 0 ,t = a & f . 1,t = b ) ) ) )
given f being Function of [:I[01] ,I[01] :],T such that A1:
f is continuous
and
A2:
for s being Point of I[01] holds
( f . s,0 = P . s & f . s,1 = Q . s & f . 0 ,s = a & f . 1,s = b )
; ex f being Function of [:I[01] ,I[01] :],T st
( f is continuous & ( for t being Point of I[01] holds
( f . t,0 = Q . t & f . t,1 = P . t & f . 0 ,t = a & f . 1,t = b ) ) )
set F = [:fA,fB:];
reconsider ff = f * [:fA,fB:] as Function of [:I[01] ,I[01] :],T ;
A3:
dom (L[01] (0 ,1 (#) ),((#) 0 ,1)) = the carrier of I[01]
by FUNCT_2:def 1, TOPMETR:27;
A4:
for s being Point of I[01] holds
( ff . s,0 = Q . s & ff . s,1 = P . s )
proof
let s be
Point of
I[01] ;
( ff . s,0 = Q . s & ff . s,1 = P . s )
A5:
for
t being
Point of
I[01] for
t9 being
Real st
t = t9 holds
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1
- t9
proof
let t be
Point of
I[01] ;
for t9 being Real st t = t9 holds
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1 - t9let t9 be
Real;
( t = t9 implies (L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1 - t9 )
assume A6:
t = t9
;
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1 - t9
reconsider ee =
t as
Point of
(Closed-Interval-TSpace 0 ,1) by TOPMETR:27;
A7:
(
0 ,1
(#) = 1 &
(#) 0 ,1
= 0 )
by TREAL_1:def 1, TREAL_1:def 2;
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t =
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . ee
.=
((0 - 1) * t9) + 1
by A6, A7, TREAL_1:10
.=
1
- (1 * t9)
;
hence
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1
- t9
;
verum
end;
A8:
dom (id the carrier of I[01] ) = the
carrier of
I[01]
by FUNCT_2:def 1;
A9:
dom [:fA,fB:] = [:(dom (id the carrier of I[01] )),(dom (L[01] (0 ,1 (#) ),((#) 0 ,1))):]
by FUNCT_3:def 9;
A10:
1
in dom (L[01] (0 ,1 (#) ),((#) 0 ,1))
by A3, Lm1;
then A11:
[s,1] in dom [:fA,fB:]
by A8, A9, ZFMISC_1:106;
A12:
0 in dom (L[01] (0 ,1 (#) ),((#) 0 ,1))
by A3, Lm1;
then A13:
[s,0 ] in dom [:fA,fB:]
by A8, A9, ZFMISC_1:106;
[:fA,fB:] . s,1 =
[((id the carrier of I[01] ) . s),((L[01] (0 ,1 (#) ),((#) 0 ,1)) . 1)]
by A8, A10, FUNCT_3:def 9
.=
[s,((L[01] (0 ,1 (#) ),((#) 0 ,1)) . 1[01] )]
by FUNCT_1:35
.=
[s,(1 - 1)]
by A5
.=
[s,0 ]
;
then A14:
ff . s,1 =
f . s,
0
by A11, FUNCT_1:23
.=
P . s
by A2
;
[:fA,fB:] . s,
0 =
[((id the carrier of I[01] ) . s),((L[01] (0 ,1 (#) ),((#) 0 ,1)) . 0 )]
by A8, A12, FUNCT_3:def 9
.=
[s,((L[01] (0 ,1 (#) ),((#) 0 ,1)) . 0[01] )]
by FUNCT_1:35
.=
[s,(1 - 0 )]
by A5
.=
[s,1]
;
then ff . s,
0 =
f . s,1
by A13, FUNCT_1:23
.=
Q . s
by A2
;
hence
(
ff . s,
0 = Q . s &
ff . s,1
= P . s )
by A14;
verum
end;
A15:
for t being Point of I[01] holds
( ff . 0 ,t = a & ff . 1,t = b )
proof
let t be
Point of
I[01] ;
( ff . 0 ,t = a & ff . 1,t = b )
t in the
carrier of
I[01]
;
then reconsider tt =
t as
Real by BORSUK_1:83;
for
t being
Point of
I[01] for
t9 being
Real st
t = t9 holds
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1
- t9
proof
let t be
Point of
I[01] ;
for t9 being Real st t = t9 holds
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1 - t9let t9 be
Real;
( t = t9 implies (L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1 - t9 )
assume A16:
t = t9
;
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1 - t9
reconsider ee =
t as
Point of
(Closed-Interval-TSpace 0 ,1) by TOPMETR:27;
A17:
(
0 ,1
(#) = 1 &
(#) 0 ,1
= 0 )
by TREAL_1:def 1, TREAL_1:def 2;
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t =
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . ee
.=
((0 - 1) * t9) + 1
by A16, A17, TREAL_1:10
.=
1
- (1 * t9)
;
hence
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1
- t9
;
verum
end;
then A18:
(L[01] (0 ,1 (#) ),((#) 0 ,1)) . t = 1
- tt
;
reconsider t9 = 1
- tt as
Point of
I[01] by Lm5;
A19:
dom (L[01] (0 ,1 (#) ),((#) 0 ,1)) = the
carrier of
I[01]
by FUNCT_2:def 1, TOPMETR:27;
A20:
dom (id the carrier of I[01] ) = the
carrier of
I[01]
by FUNCT_2:def 1;
then A21:
0 in dom (id the carrier of I[01] )
by Lm1;
A22:
dom [:fA,fB:] = [:(dom (id the carrier of I[01] )),(dom (L[01] (0 ,1 (#) ),((#) 0 ,1))):]
by FUNCT_3:def 9;
then A23:
[0 ,t] in dom [:fA,fB:]
by A19, A21, ZFMISC_1:106;
A24:
1
in dom (id the carrier of I[01] )
by A20, Lm1;
then A25:
[1,t] in dom [:fA,fB:]
by A19, A22, ZFMISC_1:106;
[:fA,fB:] . 1,
t =
[((id the carrier of I[01] ) . 1),((L[01] (0 ,1 (#) ),((#) 0 ,1)) . t)]
by A19, A24, FUNCT_3:def 9
.=
[1,(1 - tt)]
by A18, A24, FUNCT_1:35
;
then A26:
ff . 1,
t =
f . 1,
t9
by A25, FUNCT_1:23
.=
b
by A2
;
[:fA,fB:] . 0 ,
t =
[((id the carrier of I[01] ) . 0 ),((L[01] (0 ,1 (#) ),((#) 0 ,1)) . t)]
by A19, A21, FUNCT_3:def 9
.=
[0 ,(1 - tt)]
by A18, A21, FUNCT_1:35
;
then ff . 0 ,
t =
f . 0 ,
t9
by A23, FUNCT_1:23
.=
a
by A2
;
hence
(
ff . 0 ,
t = a &
ff . 1,
t = b )
by A26;
verum
end;
[:fA,fB:] is continuous
by Th12;
then
ff is continuous
by A1, TOPS_2:58;
hence
ex f being Function of [:I[01] ,I[01] :],T st
( f is continuous & ( for t being Point of I[01] holds
( f . t,0 = Q . t & f . t,1 = P . t & f . 0 ,t = a & f . 1,t = b ) ) )
by A4, A15; verum