let X, Y be non empty TopSpace; :: thesis: for x being Point of X
for f being Function of [:(X | {x}),Y:],Y st f = pr2 {x},the carrier of Y holds
f " = <:(Y --> x),(id Y):>
let x be Point of X; :: thesis: for f being Function of [:(X | {x}),Y:],Y st f = pr2 {x},the carrier of Y holds
f " = <:(Y --> x),(id Y):>
let f be Function of [:(X | {x}),Y:],Y; :: thesis: ( f = pr2 {x},the carrier of Y implies f " = <:(Y --> x),(id Y):> )
set Z = {x};
assume A1:
f = pr2 {x},the carrier of Y
; :: thesis: f " = <:(Y --> x),(id Y):>
then A2:
rng f = the carrier of Y
by FUNCT_3:62;
A3:
f is one-to-one
by A1, Th7;
reconsider Z = {x} as non empty Subset of X ;
reconsider idZ = Y --> x as continuous Function of Y,(X | Z) by Th2;
set idY = id Y;
reconsider KA = <:idZ,(id Y):> as continuous Function of Y,[:(X | Z),Y:] by YELLOW12:41;
A4:
rng KA c= [:(rng idZ),(rng (id Y)):]
by FUNCT_3:71;
rng idZ c= the carrier of (X | Z)
;
then A5:
rng idZ c= Z
by PRE_TOPC:29;
then
[:(rng idZ),(rng (id Y)):] c= [:{x},the carrier of Y:]
by ZFMISC_1:119;
then A6:
rng KA c= [:{x},the carrier of Y:]
by A4, XBOOLE_1:1;
[:{x},the carrier of Y:] c= rng KA
proof
let y be
set ;
:: according to TARSKI:def 3 :: thesis: ( not y in [:{x},the carrier of Y:] or y in rng KA )
assume
y in [:{x},the carrier of Y:]
;
:: thesis: y in rng KA
then consider y1,
y2 being
set such that A7:
(
y1 in {x} &
y2 in the
carrier of
Y &
y = [y1,y2] )
by ZFMISC_1:def 2;
A8:
y = [x,y2]
by A7, TARSKI:def 1;
A9:
idZ . y2 =
(the carrier of Y --> x) . y2
.=
x
by A7, FUNCOP_1:13
;
A10:
y2 in dom KA
by A7, FUNCT_2:def 1;
then KA . y2 =
[(idZ . y2),((id Y) . y2)]
by FUNCT_3:def 8
.=
[x,y2]
by A7, A9, FUNCT_1:35
;
hence
y in rng KA
by A8, A10, FUNCT_1:def 5;
:: thesis: verum
end;
then A11: rng KA =
[:Z,the carrier of Y:]
by A6, XBOOLE_0:def 10
.=
dom f
by A1, FUNCT_3:def 6
;
A12: dom idZ =
the carrier of Y
by FUNCT_2:def 1
.=
dom (id Y)
by FUNCT_2:def 1
;
rng (id Y) c= the carrier of Y
;
then
f * KA = id (rng f)
by A1, A2, A5, A12, FUNCT_3:72;
then
KA = f "
by A3, A11, FUNCT_1:64;
hence
f " = <:(Y --> x),(id Y):>
by A1, A2, Th7, TOPS_2:def 4; :: thesis: verum