let T be non empty TopSpace; for a, b being Point of T
for P being Path of a,b
for Q being constant Path of a,a st a,b are_connected holds
RePar (P,2RP) = Q + P
let a, b be Point of T; for P being Path of a,b
for Q being constant Path of a,a st a,b are_connected holds
RePar (P,2RP) = Q + P
let P be Path of a,b; for Q being constant Path of a,a st a,b are_connected holds
RePar (P,2RP) = Q + P
let Q be constant Path of a,a; ( a,b are_connected implies RePar (P,2RP) = Q + P )
assume A1:
a,b are_connected
; RePar (P,2RP) = Q + P
set f = RePar (P,2RP);
set g = Q + P;
A2:
a,a are_connected
;
for p being Element of I[01] holds (RePar (P,2RP)) . p = (Q + P) . p
proof
0 in the
carrier of
I[01]
by BORSUK_1:43;
then A3:
0 in dom Q
by FUNCT_2:def 1;
let p be
Element of
I[01];
(RePar (P,2RP)) . p = (Q + P) . p
p in the
carrier of
I[01]
;
then A4:
p in dom 2RP
by FUNCT_2:def 1;
A5:
(RePar (P,2RP)) . p =
(P * 2RP) . p
by A1, Def4, Th48
.=
P . (2RP . p)
by A4, FUNCT_1:13
;
per cases
( p <= 1 / 2 or p > 1 / 2 )
;
suppose A6:
p <= 1
/ 2
;
(RePar (P,2RP)) . p = (Q + P) . pthen
2
* p is
Point of
I[01]
by Th3;
then
2
* p in the
carrier of
I[01]
;
then A7:
2
* p in dom Q
by FUNCT_2:def 1;
(RePar (P,2RP)) . p =
P . 0
by A5, A6, Def6
.=
a
by A1, BORSUK_2:def 2
.=
Q . 0
by A2, BORSUK_2:def 2
.=
Q . (2 * p)
by A3, A7, FUNCT_1:def 10
.=
(Q + P) . p
by A1, A6, BORSUK_2:def 5
;
hence
(RePar (P,2RP)) . p = (Q + P) . p
;
verum end; end;
end;
hence
RePar (P,2RP) = Q + P
by FUNCT_2:63; verum