let S, T be non empty TopSpace; :: thesis: pr1 the carrier of S,the carrier of T is continuous Function of [:S,T:],S
set I = the carrier of S;
set J = the carrier of T;
A1:
the carrier of [:S,T:] = [:the carrier of S,the carrier of T:]
by BORSUK_1:def 5;
then reconsider f = pr1 the carrier of S,the carrier of T as Function of [:S,T:],S ;
f is continuous
proof
let w be
Point of
[:S,T:];
:: according to BORSUK_1:def 3 :: thesis: for b1 being a_neighborhood of f . w ex b2 being a_neighborhood of w st f .: b2 c= b1let G be
a_neighborhood of
f . w;
:: thesis: ex b1 being a_neighborhood of w st f .: b1 c= G
consider x,
y being
set such that A2:
(
x in the
carrier of
S &
y in the
carrier of
T &
w = [x,y] )
by A1, ZFMISC_1:def 2;
set H =
[:(Int G),([#] T):];
A3:
Int [:(Int G),([#] T):] =
[:(Int (Int G)),(Int ([#] T)):]
by BORSUK_1:47
.=
[:(Int G),([#] T):]
by TOPS_1:43
;
A4:
f . w in Int G
by CONNSP_2:def 1;
[:(Int G),([#] T):] is
a_neighborhood of
w
then reconsider H =
[:(Int G),([#] T):] as
a_neighborhood of
w ;
take
H
;
:: thesis: f .: H c= G
reconsider X =
Int G as non
empty Subset of
S by CONNSP_2:def 1;
[:X,([#] T):] <> {}
;
then
f .: H = Int G
by BORSUK_1:12;
hence
f .: H c= G
by TOPS_1:44;
:: thesis: verum
end;
hence
pr1 the carrier of S,the carrier of T is continuous Function of [:S,T:],S
; :: thesis: verum