let n be Nat; for T being TopSpace
for A being closed Subset of T st T is normal holds
for f being Function of (T | A),((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st f is continuous holds
ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f )
let T be TopSpace; for A being closed Subset of T st T is normal holds
for f being Function of (T | A),((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st f is continuous holds
ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f )
let A be closed Subset of T; ( T is normal implies for f being Function of (T | A),((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st f is continuous holds
ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f ) )
assume A1:
T is normal
; for f being Function of (T | A),((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st f is continuous holds
ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f )
set TR = TOP-REAL n;
set N = 0. (TOP-REAL n);
set H = ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1));
let f be Function of (T | A),((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))); ( f is continuous implies ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f ) )
assume A2:
f is continuous
; ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f )
A3:
[#] ((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) = ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1))
by PRE_TOPC:def 5;
A4:
[#] (T | A) = A
by PRE_TOPC:def 5;
per cases
( A is empty or not A is empty )
;
suppose A7:
not
A is
empty
;
ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f )set CC =
Closed-Interval-TSpace (
(- 1),1);
per cases
( n = 0 or n <> 0 )
;
suppose A8:
n = 0
;
ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f )reconsider TRH =
(TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1))) as non
empty TopSpace ;
A9:
{(0. (TOP-REAL n))} = the
carrier of
(TOP-REAL n)
by EUCLID:22, A8, JORDAN2C:105;
then reconsider Z =
0. (TOP-REAL n) as
Point of
TRH by A3, ZFMISC_1:33;
ClosedHypercube (
(0. (TOP-REAL n)),
(n |-> 1))
= the
carrier of
(TOP-REAL n)
by A9, ZFMISC_1:33;
then A10:
rng f = the
carrier of
(TOP-REAL n)
by A4, A7, A3, A9, ZFMISC_1:33;
reconsider g =
T --> Z as
Function of
T,
((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) ;
take
g
;
( g is continuous & g | A = f )A11:
the
carrier of
T /\ A = A
by XBOOLE_1:28;
dom f = A
by FUNCT_2:def 1, A4;
then
f = A --> (0. (TOP-REAL n))
by A10, FUNCOP_1:9, EUCLID:22, A8, JORDAN2C:105;
hence
(
g is
continuous &
g | A = f )
by A11, FUNCOP_1:12;
verum end; suppose
n <> 0
;
ex g being Function of T,((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) st
( g is continuous & g | A = f )then reconsider nn =
n as non
zero Element of
NAT by ORDINAL1:def 12;
set CC =
Closed-Interval-TSpace (
(- 1),1);
reconsider F =
f as
Function of
(T | A),
(TOP-REAL n) by FUNCT_2:7, A3;
defpred S1[
Nat,
object ]
means ex
g being
continuous Function of
T,
R^1 st
( $2
= g &
rng g c= [#] (Closed-Interval-TSpace ((- 1),1)) &
g | A = (PROJ (n,$1)) * F );
A12:
dom f = A
by A4, FUNCT_2:def 1;
0. (TOP-REAL n) = 0* n
by EUCLID:70;
then A13:
0. (TOP-REAL n) = n |-> 0
by EUCLID:def 4;
A14:
for
k being
Nat st
k in Seg n holds
ex
x being
object st
S1[
k,
x]
proof
A15:
the
carrier of
(Closed-Interval-TSpace ((- 1),1)) = [.(- 1),1.]
by TOPMETR:18;
A16:
not
T is
empty
by A7;
let k be
Nat;
( k in Seg n implies ex x being object st S1[k,x] )
assume A17:
k in Seg n
;
ex x being object st S1[k,x]
rng f c= ClosedHypercube (
(0. (TOP-REAL n)),
(n |-> 1))
by A3;
then
(PROJ (n,k)) .: (rng F) c= (PROJ (n,k)) .: (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))
by RELAT_1:123;
then A18:
(PROJ (n,k)) .: (rng F) c= [.(((0. (TOP-REAL n)) . k) - ((n |-> 1) . k)),(((0. (TOP-REAL n)) . k) + ((n |-> 1) . k)).]
by A17, Th7;
A19:
dom ((PROJ (n,k)) * F) = the
carrier of
(T | A)
by FUNCT_2:def 1;
A20:
(0. (TOP-REAL n)) . k = 0
by A13;
(n |-> 1) . k = 1
by A17, FINSEQ_2:57;
then
rng ((PROJ (n,k)) * F) c= [.(- 1),1.]
by A20, A18, RELAT_1:127;
then reconsider PF =
(PROJ (n,k)) * F as
Function of
(T | A),
(Closed-Interval-TSpace ((- 1),1)) by A19, A15, FUNCT_2:2;
A21:
F is
continuous
by A2, PRE_TOPC:26;
PROJ (
n,
k) is
continuous
by TOPREALC:57, A17;
then consider g being
continuous Function of
T,
(Closed-Interval-TSpace ((- 1),1)) such that A22:
g | A = PF
by A21, A16, A7, PRE_TOPC:27, A1, TIETZE:23;
A23:
rng g c= REAL
;
dom g = the
carrier of
T
by FUNCT_2:def 1;
then reconsider G =
g as
Function of
T,
R^1 by A23, TOPMETR:17, FUNCT_2:2;
A24:
G is
continuous
by PRE_TOPC:26;
rng g c= the
carrier of
(Closed-Interval-TSpace ((- 1),1))
by RELAT_1:def 19;
hence
ex
x being
object st
S1[
k,
x]
by A24, A22;
verum
end; consider pp being
FinSequence such that A25:
dom pp = Seg n
and A26:
for
k being
Nat st
k in Seg n holds
S1[
k,
pp . k]
from FINSEQ_1:sch 1(A14);
A27:
len pp = nn
by A25, FINSEQ_1:def 3;
rng pp c= Funcs ( the
carrier of
T, the
carrier of
R^1)
proof
let y be
object ;
TARSKI:def 3 ( not y in rng pp or y in Funcs ( the carrier of T, the carrier of R^1) )
assume
y in rng pp
;
y in Funcs ( the carrier of T, the carrier of R^1)
then consider k being
object such that A28:
k in dom pp
and A29:
pp . k = y
by FUNCT_1:def 3;
reconsider k =
k as
Nat by A28;
consider g being
continuous Function of
T,
R^1 such that A30:
pp . k = g
and
rng g c= [#] (Closed-Interval-TSpace ((- 1),1))
and
g | A = (PROJ (n,k)) * F
by A25, A26, A28;
A31:
rng g c= the
carrier of
R^1
by RELAT_1:def 19;
dom g = the
carrier of
T
by FUNCT_2:def 1;
hence
y in Funcs ( the
carrier of
T, the
carrier of
R^1)
by A31, FUNCT_2:def 2, A29, A30;
verum
end; then
pp is
FinSequence of
Funcs ( the
carrier of
T, the
carrier of
R^1)
by FINSEQ_1:def 4;
then reconsider pp =
pp as
Element of
nn -tuples_on (Funcs ( the carrier of T, the carrier of R^1)) by A27, FINSEQ_2:92;
A32:
dom <:pp:> = the
carrier of
T
by FUNCT_2:def 1;
A33:
the
carrier of
(Closed-Interval-TSpace ((- 1),1)) = [.(- 1),1.]
by TOPMETR:18;
rng <:pp:> c= ClosedHypercube (
(0. (TOP-REAL n)),
(n |-> 1))
proof
let y be
object ;
TARSKI:def 3 ( not y in rng <:pp:> or y in ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)) )
assume A34:
y in rng <:pp:>
;
y in ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1))
then consider x being
object such that A35:
x in dom <:pp:>
and A36:
<:pp:> . x = y
by FUNCT_1:def 3;
reconsider p =
<:pp:> . x as
Point of
(TOP-REAL n) by A34, A36;
now for j being Nat st j in Seg n holds
p . j in [.(((0. (TOP-REAL n)) . j) - ((n |-> 1) . j)),(((0. (TOP-REAL n)) . j) + ((n |-> 1) . j)).]let j be
Nat;
( j in Seg n implies p . j in [.(((0. (TOP-REAL n)) . j) - ((n |-> 1) . j)),(((0. (TOP-REAL n)) . j) + ((n |-> 1) . j)).] )A37:
(0. (TOP-REAL n)) . j = 0
by A13;
assume A38:
j in Seg n
;
p . j in [.(((0. (TOP-REAL n)) . j) - ((n |-> 1) . j)),(((0. (TOP-REAL n)) . j) + ((n |-> 1) . j)).]then consider g being
continuous Function of
T,
R^1 such that A39:
g = pp . j
and A40:
rng g c= [#] (Closed-Interval-TSpace ((- 1),1))
and
g | A = (PROJ (n,j)) * F
by A26;
A41:
dom g = the
carrier of
T
by FUNCT_2:def 1;
g . x = p . j
by Th20, A39;
then A42:
p . j in rng g
by A41, A35, FUNCT_1:def 3;
(n |-> 1) . j = 1
by A38, FINSEQ_2:57;
hence
p . j in [.(((0. (TOP-REAL n)) . j) - ((n |-> 1) . j)),(((0. (TOP-REAL n)) . j) + ((n |-> 1) . j)).]
by A37, A42, A40, A33;
verum end;
hence
y in ClosedHypercube (
(0. (TOP-REAL n)),
(n |-> 1))
by Def2, A36;
verum
end; then reconsider G =
<:pp:> as
Function of
T,
((TOP-REAL n) | (ClosedHypercube ((0. (TOP-REAL n)),(n |-> 1)))) by A3, A32, FUNCT_2:2;
take
G
;
( G is continuous & G | A = f )
for
i being
Nat st
i in dom pp holds
for
h being
Function of
T,
R^1 st
h = pp . i holds
h is
continuous
hence
G is
continuous
by Th21, PRE_TOPC:27;
G | A = fA44:
dom (G | A) = A
by A32, RELAT_1:62;
for
e being
set st
e in dom f holds
(G | A) . e = f . e
proof
let e be
set ;
( e in dom f implies (G | A) . e = f . e )
A45:
rng F c= the
carrier of
(TOP-REAL n)
;
assume A46:
e in dom f
;
(G | A) . e = f . e
then
G . e in rng G
by A32, A12, FUNCT_1:def 3;
then A47:
G . e in ClosedHypercube (
(0. (TOP-REAL n)),
(n |-> 1))
by A3;
f . e in rng f
by A46, FUNCT_1:def 3;
then reconsider Ge =
G . e,
fe =
f . e as
Point of
(TOP-REAL n) by A45, A47;
A48:
len fe = n
by CARD_1:def 7;
A49:
now for w being Nat st 1 <= w & w <= n holds
Ge . w = fe . wA50:
dom fe = Seg n
by A48, FINSEQ_1:def 3;
let w be
Nat;
( 1 <= w & w <= n implies Ge . w = fe . w )assume that A51:
1
<= w
and A52:
w <= n
;
Ge . w = fe . wconsider g being
continuous Function of
T,
R^1 such that A53:
g = pp . w
and
rng g c= [#] (Closed-Interval-TSpace ((- 1),1))
and A54:
g | A = (PROJ (n,w)) * F
by A51, A52, FINSEQ_1:1, A26;
A55:
Ge . w = g . e
by Th20, A53;
A56:
e in dom (g | A)
by A46, A12, FUNCT_2:def 1;
(g | A) . e = g . e
by A46, A4, FUNCT_1:49;
then
Ge . w = (PROJ (n,w)) . fe
by A55, A56, A54, FUNCT_1:12;
hence Ge . w =
fe /. w
by TOPREALC:def 6
.=
fe . w
by PARTFUN1:def 6, A51, A52, FINSEQ_1:1, A50
;
verum end;
A57:
len Ge = n
by CARD_1:def 7;
(G | A) . e = G . e
by A46, A44, A4, FUNCT_1:47;
hence
(G | A) . e = f . e
by A49, FINSEQ_1:14, A57, A48;
verum
end; hence
G | A = f
by A44, A12;
verum end; end; end; end;