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 b,b st a,b are_connected holds
RePar (P,1RP) = P + Q
let a, b be Point of T; for P being Path of a,b
for Q being constant Path of b,b st a,b are_connected holds
RePar (P,1RP) = P + Q
let P be Path of a,b; for Q being constant Path of b,b st a,b are_connected holds
RePar (P,1RP) = P + Q
let Q be constant Path of b,b; ( a,b are_connected implies RePar (P,1RP) = P + Q )
set f = RePar (P,1RP);
set g = P + Q;
assume A1:
a,b are_connected
; RePar (P,1RP) = P + Q
A2:
b,b are_connected
;
for p being Element of I[01] holds (RePar (P,1RP)) . p = (P + Q) . 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,1RP)) . p = (P + Q) . p
p in the
carrier of
I[01]
;
then A4:
p in dom 1RP
by FUNCT_2:def 1;
A5:
(RePar (P,1RP)) . p =
(P * 1RP) . p
by A1, Def4, Th47
.=
P . (1RP . p)
by A4, FUNCT_1:13
;
per cases
( p <= 1 / 2 or p > 1 / 2 )
;
suppose A7:
p > 1
/ 2
;
(RePar (P,1RP)) . p = (P + Q) . pthen
(2 * p) - 1 is
Point of
I[01]
by Th4;
then
(2 * p) - 1
in the
carrier of
I[01]
;
then A8:
(2 * p) - 1
in dom Q
by FUNCT_2:def 1;
(RePar (P,1RP)) . p =
P . 1
by A5, A7, Def5
.=
b
by A1, BORSUK_2:def 2
.=
Q . 0
by A2, BORSUK_2:def 2
.=
Q . ((2 * p) - 1)
by A3, A8, FUNCT_1:def 10
.=
(P + Q) . p
by A1, A7, BORSUK_2:def 5
;
hence
(RePar (P,1RP)) . p = (P + Q) . p
;
verum end; end;
end;
hence
RePar (P,1RP) = P + Q
by FUNCT_2:63; verum