let X, Y be non empty TopSpace; 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; 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; ( f = pr2 ({x}, the carrier of Y) implies f " = <:(Y --> x),(id Y):> )
set Z = {x};
set idY = id Y;
A1:
rng (id Y) c= the carrier of Y
;
assume A2:
f = pr2 ({x}, the carrier of Y)
; f " = <:(Y --> x),(id Y):>
then A3:
rng f = the carrier of Y
by FUNCT_3:46;
reconsider Z = {x} as non empty Subset of X ;
reconsider idZ = Y --> x as continuous Function of Y,(X | Z) by Th2;
reconsider KA = <:idZ,(id Y):> as continuous Function of Y,[:(X | Z),Y:] by YELLOW12:41;
A4:
[:{x}, the carrier of Y:] c= rng KA
proof
let y be
object ;
TARSKI:def 3 ( not y in [:{x}, the carrier of Y:] or y in rng KA )
assume
y in [:{x}, the carrier of Y:]
;
y in rng KA
then consider y1,
y2 being
object such that A5:
y1 in {x}
and A6:
y2 in the
carrier of
Y
and A7:
y = [y1,y2]
by ZFMISC_1:def 2;
A8:
y = [x,y2]
by A5, A7, TARSKI:def 1;
A9:
idZ . y2 =
( the carrier of Y --> x) . y2
.=
x
by A6, FUNCOP_1:7
;
A10:
y2 in dom KA
by A6, FUNCT_2:def 1;
then KA . y2 =
[(idZ . y2),((id Y) . y2)]
by FUNCT_3:def 7
.=
[x,y2]
by A6, A9, FUNCT_1:18
;
hence
y in rng KA
by A8, A10, FUNCT_1:def 3;
verum
end;
rng idZ c= the carrier of (X | Z)
;
then A11:
rng idZ c= Z
by PRE_TOPC:8;
then
( rng KA c= [:(rng idZ),(rng (id Y)):] & [:(rng idZ),(rng (id Y)):] c= [:{x}, the carrier of Y:] )
by FUNCT_3:51, ZFMISC_1:96;
then
rng KA c= [:{x}, the carrier of Y:]
;
then A12: rng KA =
[:Z, the carrier of Y:]
by A4
.=
dom f
by A2, FUNCT_3:def 5
;
A13:
f is one-to-one
by A2, Th5;
A14:
f is onto
by A3, FUNCT_2:def 3;
dom idZ =
the carrier of Y
by FUNCT_2:def 1
.=
dom (id Y)
by FUNCT_2:def 1
;
then
f * KA = id (rng f)
by A2, A3, A11, A1, FUNCT_3:52;
then
KA = f "
by A13, A12, FUNCT_1:42;
hence
f " = <:(Y --> x),(id Y):>
by A13, A14, TOPS_2:def 4; verum