let M be non empty MetrSpace; for S being non empty compact TopSpace
for T being non empty MetrSpace
for G being Subset of (Funcs ( the carrier of M, the carrier of T))
for H being non empty Subset of (MetricSpace_of_ContinuousFunctions (S,T)) st S = TopSpaceMetr M & T is complete & G = H holds
( (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded iff ( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) ) )
let S be non empty compact TopSpace; for T being non empty MetrSpace
for G being Subset of (Funcs ( the carrier of M, the carrier of T))
for H being non empty Subset of (MetricSpace_of_ContinuousFunctions (S,T)) st S = TopSpaceMetr M & T is complete & G = H holds
( (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded iff ( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) ) )
let T be non empty MetrSpace; for G being Subset of (Funcs ( the carrier of M, the carrier of T))
for H being non empty Subset of (MetricSpace_of_ContinuousFunctions (S,T)) st S = TopSpaceMetr M & T is complete & G = H holds
( (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded iff ( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) ) )
let G be Subset of (Funcs ( the carrier of M, the carrier of T)); for H being non empty Subset of (MetricSpace_of_ContinuousFunctions (S,T)) st S = TopSpaceMetr M & T is complete & G = H holds
( (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded iff ( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) ) )
let H be non empty Subset of (MetricSpace_of_ContinuousFunctions (S,T)); ( S = TopSpaceMetr M & T is complete & G = H implies ( (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded iff ( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) ) ) )
assume A1:
( S = TopSpaceMetr M & T is complete )
; ( not G = H or ( (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded iff ( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) ) ) )
assume A2:
G = H
; ( (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded iff ( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) ) )
set Z = MetricSpace_of_ContinuousFunctions (S,T);
set MZH = (MetricSpace_of_ContinuousFunctions (S,T)) | H;
A3:
the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) = H
by TOPMETR:def 2;
assume A6:
( G is equicontinuous & ( for x being Point of S
for Hx being non empty Subset of T st Hx = { (f . x) where f is Function of S,T : f in H } holds
T | (Cl Hx) is compact ) )
; (MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded
for e being Real st e > 0 holds
ex L being Subset-Family of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
( L is finite & the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) = union L & ( for C being Subset of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C in L holds
ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e) ) )
proof
let e0 be
Real;
( e0 > 0 implies ex L being Subset-Family of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
( L is finite & the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) = union L & ( for C being Subset of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C in L holds
ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e0) ) ) )
assume A7:
e0 > 0
;
ex L being Subset-Family of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
( L is finite & the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) = union L & ( for C being Subset of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C in L holds
ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e0) ) )
then A8:
(
0 < e0 / 2 &
e0 / 2
< e0 )
by XREAL_1:216;
set e =
e0 / 2;
consider d being
Real such that A9:
(
0 < d & ( for
f being
Function of the
carrier of
M, the
carrier of
T st
f in G holds
for
x1,
x2 being
Point of
M st
dist (
x1,
x2)
< d holds
dist (
(f . x1),
(f . x2))
< (e0 / 2) / 4 ) )
by A6, A7;
set BM =
{ (Ball (x0,d)) where x0 is Element of M : verum } ;
{ (Ball (x0,d)) where x0 is Element of M : verum } c= bool the
carrier of
S
then reconsider BM =
{ (Ball (x0,d)) where x0 is Element of M : verum } as
Subset-Family of
S ;
for
P being
Subset of
S st
P in BM holds
P is
open
then A12:
BM is
open
by TOPS_2:def 1;
the
carrier of
S c= union BM
then
BM is
Cover of
[#] S
by SETFAM_1:def 11;
then consider BM0 being
Subset-Family of
S such that A14:
(
BM0 c= BM &
BM0 is
Cover of
[#] S &
BM0 is
finite )
by COMPTS_1:def 4, COMPTS_1:1, A12;
reconsider BM0 =
BM0 as
finite set by A14;
defpred S1[
object ,
object ]
means ex
w being
Point of
M st
( $2
= w & $1
= Ball (
w,
d) );
A15:
for
D being
object st
D in BM holds
ex
w being
object st
(
w in the
carrier of
M &
S1[
D,
w] )
consider U being
Function of
BM, the
carrier of
M such that A17:
for
D being
object st
D in BM holds
S1[
D,
U . D]
from FUNCT_2:sch 1(A15);
A18:
for
D being
object st
D in BM holds
D = Ball (
(U /. D),
d)
set CF =
canFS BM0;
A21:
len (canFS BM0) = card BM0
by FINSEQ_1:93;
A22:
rng (canFS BM0) = BM0
by FUNCT_2:def 3;
A23:
dom U = BM
by FUNCT_2:def 1;
then reconsider PS =
U * (canFS BM0) as
FinSequence by A22, A14, FINSEQ_1:16;
rng PS c= rng U
by RELAT_1:26;
then reconsider PS =
PS as
FinSequence of the
carrier of
S by FINSEQ_1:def 4, A1, XBOOLE_1:1;
A24:
dom PS =
dom (canFS BM0)
by A22, A23, A14, RELAT_1:27
.=
Seg (card BM0)
by A21, FINSEQ_1:def 3
;
A25:
dom (canFS BM0) =
Seg (len (canFS BM0))
by FINSEQ_1:def 3
.=
dom PS
by A24, FINSEQ_1:93
;
A26:
for
i being
Nat st
i in dom PS holds
(canFS BM0) . i = Ball (
((U * (canFS BM0)) /. i),
d)
proof
let i be
Nat;
( i in dom PS implies (canFS BM0) . i = Ball (((U * (canFS BM0)) /. i),d) )
assume A27:
i in dom PS
;
(canFS BM0) . i = Ball (((U * (canFS BM0)) /. i),d)
then A28:
(canFS BM0) . i in rng (canFS BM0)
by FUNCT_1:3, A25;
then U /. ((canFS BM0) . i) =
U . ((canFS BM0) . i)
by PARTFUN1:def 6, A23, A14
.=
PS . i
by FUNCT_1:12, A27
.=
(U * (canFS BM0)) /. i
by PARTFUN1:def 6, A27
;
hence
(canFS BM0) . i = Ball (
((U * (canFS BM0)) /. i),
d)
by A28, A18, A14;
verum
end;
union (rng (canFS BM0)) = union BM0
by FUNCT_2:def 3;
then A29:
the
carrier of
S c= union (rng (canFS BM0))
by A14, SETFAM_1:def 11;
A30:
BM0 <> {}
defpred S2[
object ,
object ]
means ex
x being
Point of
S ex
NHx,
CHx being non
empty Subset of
T st
( $1
= x &
NHx = { (f . x) where f is Function of S,T : f in H } & $2
= Cl NHx );
A31:
for
x being
object st
x in the
carrier of
S holds
ex
B being
object st
(
B in bool the
carrier of
T &
S2[
x,
B] )
proof
let x be
object ;
( x in the carrier of S implies ex B being object st
( B in bool the carrier of T & S2[x,B] ) )
assume
x in the
carrier of
S
;
ex B being object st
( B in bool the carrier of T & S2[x,B] )
then reconsider x0 =
x as
Point of
S ;
set NHx =
{ (f . x0) where f is Function of S,T : f in H } ;
consider f0 being
object such that A32:
f0 in H
by XBOOLE_0:def 1;
f0 in MetricSpace_of_ContinuousFunctions (
S,
T)
by A32;
then
ex
g being
Function of the
carrier of
S,
(TopSpaceMetr T) st
(
f0 = g &
g is
continuous )
;
then reconsider g =
f0 as
Function of
S,
T ;
A33:
g . x0 in { (f . x0) where f is Function of S,T : f in H }
by A32;
{ (f . x0) where f is Function of S,T : f in H } c= the
carrier of
T
then reconsider NHx =
{ (f . x0) where f is Function of S,T : f in H } as non
empty Subset of
T by A33;
reconsider CHx =
Cl NHx as non
empty Subset of
T ;
CHx in bool the
carrier of
T
;
hence
ex
B being
object st
(
B in bool the
carrier of
T &
S2[
x,
B] )
;
verum
end;
consider ST being
Function of the
carrier of
S,
(bool the carrier of T) such that A35:
for
x being
object st
x in the
carrier of
S holds
S2[
x,
ST . x]
from FUNCT_2:sch 1(A31);
A36:
dom ST = the
carrier of
S
by FUNCT_2:def 1;
A37:
rng PS c= the
carrier of
S
;
then reconsider STPS =
ST * PS as
FinSequence by A36, FINSEQ_1:16;
rng STPS c= rng ST
by RELAT_1:26;
then reconsider STPS =
STPS as
FinSequence of
bool the
carrier of
(TopSpaceMetr T) by FINSEQ_1:def 4, XBOOLE_1:1;
A38:
dom STPS = Seg (card BM0)
by A24, A36, A37, RELAT_1:27;
A39:
for
i being
Nat st
i in dom STPS holds
( ex
NHx,
CHx being non
empty Subset of
T st
(
NHx = { (f . (PS /. i)) where f is Function of S,T : f in H } &
STPS /. i = Cl NHx ) & not
STPS /. i is
empty )
proof
let i be
Nat;
( i in dom STPS implies ( ex NHx, CHx being non empty Subset of T st
( NHx = { (f . (PS /. i)) where f is Function of S,T : f in H } & STPS /. i = Cl NHx ) & not STPS /. i is empty ) )
assume A40:
i in dom STPS
;
( ex NHx, CHx being non empty Subset of T st
( NHx = { (f . (PS /. i)) where f is Function of S,T : f in H } & STPS /. i = Cl NHx ) & not STPS /. i is empty )
then A41:
STPS /. i =
STPS . i
by PARTFUN1:def 6
.=
ST . (PS . i)
by FUNCT_1:12, A40
;
consider x being
Point of
S,
NHx,
CHx being non
empty Subset of
T such that A42:
(
PS /. i = x &
NHx = { (f . x) where f is Function of S,T : f in H } &
ST . (PS /. i) = Cl NHx )
by A35;
A43:
STPS /. i = Cl NHx
by A42, A41, A38, A24, A40, PARTFUN1:def 6;
consider f0 being
object such that A44:
f0 in H
by XBOOLE_0:def 1;
f0 in MetricSpace_of_ContinuousFunctions (
S,
T)
by A44;
then
ex
g being
Function of
S,
(TopSpaceMetr T) st
(
f0 = g &
g is
continuous )
;
then reconsider g =
f0 as
Function of
S,
T ;
thus
( ex
NHx,
CHx being non
empty Subset of
T st
(
NHx = { (f . (PS /. i)) where f is Function of S,T : f in H } &
STPS /. i = Cl NHx ) & not
STPS /. i is
empty )
by A42, A43;
verum
end;
for
i being
Nat st
i in Seg (len STPS) holds
STPS /. i is
compact
then A47:
union (rng STPS) is
compact
by ASCOLI:2;
consider i0 being
object such that A48:
i0 in dom STPS
by A30, A38, XBOOLE_0:def 1;
reconsider i0 =
i0 as
Nat by A48;
STPS /. i0 = STPS . i0
by A48, PARTFUN1:def 6;
then
STPS /. i0 c= union (rng STPS)
by ZFMISC_1:74, A48, FUNCT_1:3;
then reconsider URSTPS =
union (rng STPS) as non
empty Subset of
T by A48, A39;
URSTPS is
sequentially_compact
by A47, TOPMETR4:15;
then A49:
T | URSTPS is
compact
by TOPMETR4:14;
set MURSTPS =
T | URSTPS;
set BM2 =
{ (Ball (w,((e0 / 2) / 4))) where w is Element of (T | URSTPS) : verum } ;
{ (Ball (w,((e0 / 2) / 4))) where w is Element of (T | URSTPS) : verum } c= bool the
carrier of
(T | URSTPS)
then reconsider BM2 =
{ (Ball (w,((e0 / 2) / 4))) where w is Element of (T | URSTPS) : verum } as
Subset-Family of
(T | URSTPS) ;
A51:
for
P being
set st
P in BM2 holds
ex
x0 being
Point of
(T | URSTPS) ex
r being
Real st
P = Ball (
x0,
r)
proof
let P be
set ;
( P in BM2 implies ex x0 being Point of (T | URSTPS) ex r being Real st P = Ball (x0,r) )
assume
P in BM2
;
ex x0 being Point of (T | URSTPS) ex r being Real st P = Ball (x0,r)
then consider x0 being
Point of
(T | URSTPS) such that A52:
P = Ball (
x0,
((e0 / 2) / 4))
;
take
x0
;
ex r being Real st P = Ball (x0,r)
take
(e0 / 2) / 4
;
P = Ball (x0,((e0 / 2) / 4))
thus
P = Ball (
x0,
((e0 / 2) / 4))
by A52;
verum
end;
the
carrier of
(T | URSTPS) c= union BM2
then
BM2 is
Cover of
[#] (T | URSTPS)
by SETFAM_1:def 11;
then consider BM02 being
Subset-Family of
(T | URSTPS) such that A54:
(
BM02 c= BM2 &
BM02 is
Cover of
[#] (T | URSTPS) &
BM02 is
finite )
by A49, TOPMETR:16, A51, TOPMETR:def 4;
reconsider BM02 =
BM02 as
finite set by A54;
A55:
BM02 <> {}
defpred S3[
object ,
object ]
means ex
w being
Point of
(T | URSTPS) st
( $2
= w & $1
= Ball (
w,
((e0 / 2) / 4)) );
A56:
for
D being
object st
D in BM2 holds
ex
w being
object st
(
w in the
carrier of
(T | URSTPS) &
S3[
D,
w] )
consider U2 being
Function of
BM2, the
carrier of
(T | URSTPS) such that A58:
for
D being
object st
D in BM2 holds
S3[
D,
U2 . D]
from FUNCT_2:sch 1(A56);
A59:
for
D being
object st
D in BM2 holds
D = Ball (
(U2 /. D),
((e0 / 2) / 4))
set CF2 =
canFS BM02;
A62:
len (canFS BM02) = card BM02
by FINSEQ_1:93;
A63:
rng (canFS BM02) = BM02
by FUNCT_2:def 3;
A64:
dom U2 = BM2
by FUNCT_2:def 1;
then reconsider PS2 =
U2 * (canFS BM02) as
FinSequence by A63, A54, FINSEQ_1:16;
rng PS2 c= rng U2
by RELAT_1:26;
then reconsider PS2 =
PS2 as
FinSequence of the
carrier of
(T | URSTPS) by FINSEQ_1:def 4, XBOOLE_1:1;
A65:
dom PS2 =
dom (canFS BM02)
by A63, A64, A54, RELAT_1:27
.=
Seg (card BM02)
by A62, FINSEQ_1:def 3
;
A66:
dom (canFS BM02) =
Seg (len (canFS BM02))
by FINSEQ_1:def 3
.=
dom PS2
by A65, FINSEQ_1:93
;
A67:
for
i being
Nat st
i in dom PS2 holds
(canFS BM02) . i = Ball (
((U2 * (canFS BM02)) /. i),
((e0 / 2) / 4))
proof
let i be
Nat;
( i in dom PS2 implies (canFS BM02) . i = Ball (((U2 * (canFS BM02)) /. i),((e0 / 2) / 4)) )
assume A68:
i in dom PS2
;
(canFS BM02) . i = Ball (((U2 * (canFS BM02)) /. i),((e0 / 2) / 4))
A69:
(canFS BM02) . i in rng (canFS BM02)
by FUNCT_1:3, A66, A68;
then U2 /. ((canFS BM02) . i) =
U2 . ((canFS BM02) . i)
by PARTFUN1:def 6, A64, A54
.=
PS2 . i
by FUNCT_1:12, A68
.=
(U2 * (canFS BM02)) /. i
by PARTFUN1:def 6, A68
;
hence
(canFS BM02) . i = Ball (
((U2 * (canFS BM02)) /. i),
((e0 / 2) / 4))
by A69, A59, A54;
verum
end;
union (rng (canFS BM02)) = union BM02
by FUNCT_2:def 3;
then A70:
the
carrier of
(T | URSTPS) c= union (rng (canFS BM02))
by A54, SETFAM_1:def 11;
defpred S4[
object ,
object ]
means ex
sigm being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) st
( $1
= sigm & $2
= { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) } );
A71:
for
x being
object st
x in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02)))) holds
ex
B being
object st
(
B in bool the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) &
S4[
x,
B] )
proof
let x be
object ;
( x in Funcs ((Seg (len PS)),(Seg (len (canFS BM02)))) implies ex B being object st
( B in bool the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) & S4[x,B] ) )
assume
x in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02))))
;
ex B being object st
( B in bool the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) & S4[x,B] )
then reconsider sigm =
x as
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) by FUNCT_2:66;
set NHx =
{ f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) } ;
{ f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) } c= the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H)
proof
let z be
object ;
TARSKI:def 3 ( not z in { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) } or z in the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) )
assume
z in { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) }
;
z in the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H)
then
ex
f being
Function of
S,
T st
(
z = f &
f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for
i being
Nat st
i in Seg (len PS) holds
f . (PS /. i) in Ball (
((U2 * (canFS BM02)) /. (sigm . i)),
((e0 / 2) / 4)) ) )
;
hence
z in the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H)
;
verum
end;
hence
ex
B being
object st
(
B in bool the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) &
S4[
x,
B] )
;
verum
end;
consider BST being
Function of
(Funcs ((Seg (len PS)),(Seg (len (canFS BM02))))),
(bool the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H)) such that A72:
for
x being
object st
x in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02)))) holds
S4[
x,
BST . x]
from FUNCT_2:sch 1(A71);
A73:
for
sigm being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) holds
BST . sigm = { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) }
proof
let sigm be
Function of
(Seg (len PS)),
(Seg (len (canFS BM02)));
BST . sigm = { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) }
sigm in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02))))
by FUNCT_2:8, A55;
then
ex
sigm1 being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) st
(
sigm = sigm1 &
BST . sigm = { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm1 . i)),((e0 / 2) / 4)) ) ) } )
by A72;
hence
BST . sigm = { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) }
;
verum
end;
A74:
Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02))))
c= bool [:(Seg (len PS)),(Seg (len (canFS BM02))):]
A75:
for
sigm being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) for
f,
g being
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
f in BST . sigm &
g in BST . sigm holds
dist (
f,
g)
< e0
proof
let sigm be
Function of
(Seg (len PS)),
(Seg (len (canFS BM02)));
for f, g being Point of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st f in BST . sigm & g in BST . sigm holds
dist (f,g) < e0let f,
g be
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H);
( f in BST . sigm & g in BST . sigm implies dist (f,g) < e0 )
assume A76:
(
f in BST . sigm &
g in BST . sigm )
;
dist (f,g) < e0
A77:
BST . sigm = { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) }
by A73;
then A78:
ex
f0 being
Function of
S,
T st
(
f = f0 &
f0 in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for
i being
Nat st
i in Seg (len PS) holds
f0 . (PS /. i) in Ball (
((U2 * (canFS BM02)) /. (sigm . i)),
((e0 / 2) / 4)) ) )
by A76;
then reconsider f0 =
f as
Function of
S,
T ;
reconsider f1 =
f0 as
Function of
M,
T by A1;
A79:
ex
f0 being
Function of
S,
T st
(
g = f0 &
f0 in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for
i being
Nat st
i in Seg (len PS) holds
f0 . (PS /. i) in Ball (
((U2 * (canFS BM02)) /. (sigm . i)),
((e0 / 2) / 4)) ) )
by A76, A77;
then reconsider g0 =
g as
Function of
S,
T ;
reconsider g1 =
g0 as
Function of
M,
T by A1;
A80:
for
x being
Point of
S holds
dist (
(f0 . x),
(g0 . x))
<= e0 / 2
proof
let x be
Point of
S;
dist ((f0 . x),(g0 . x)) <= e0 / 2
x in union (rng (canFS BM0))
by A29;
then consider D being
set such that A81:
(
x in D &
D in rng (canFS BM0) )
by TARSKI:def 4;
consider i being
object such that A82:
(
i in dom (canFS BM0) &
D = (canFS BM0) . i )
by A81, FUNCT_1:def 3;
reconsider i =
i as
Nat by A82;
A83:
x in Ball (
((U * (canFS BM0)) /. i),
d)
by A82, A81, A25, A26;
A84:
PS /. i =
PS . i
by A25, A82, PARTFUN1:def 6
.=
(U * (canFS BM0)) /. i
by A25, A82, PARTFUN1:def 6
;
reconsider ym =
(U * (canFS BM0)) /. i as
Point of
M ;
reconsider ys =
PS /. i as
Point of
S ;
x in { z where z is Point of M : dist (ym,z) < d }
by METRIC_1:def 14, A83;
then A85:
ex
z being
Point of
M st
(
x = z &
dist (
ym,
z)
< d )
;
then reconsider xm =
x as
Point of
M ;
A86:
dist (
(f1 . ym),
(f1 . xm))
< (e0 / 2) / 4
by A3, A9, A85, A2;
A87:
dist (
(g1 . ym),
(g1 . xm))
< (e0 / 2) / 4
by A3, A9, A85, A2;
i in Seg (len PS)
by A25, A82, FINSEQ_1:def 3;
then
f0 . ys in Ball (
((U2 * (canFS BM02)) /. (sigm . i)),
((e0 / 2) / 4))
by A78;
then
f0 . ys in { y where y is Element of (T | URSTPS) : dist (((U2 * (canFS BM02)) /. (sigm . i)),y) < (e0 / 2) / 4 }
by METRIC_1:def 14;
then A88:
ex
y being
Element of
(T | URSTPS) st
(
f0 . ys = y &
dist (
((U2 * (canFS BM02)) /. (sigm . i)),
y)
< (e0 / 2) / 4 )
;
then reconsider f0ys =
f0 . ys as
Point of
(T | URSTPS) ;
reconsider u2cf2n =
(U2 * (canFS BM02)) /. (sigm . i) as
Point of
T by TOPMETR:def 1, TARSKI:def 3;
reconsider f0ysm =
f0ys as
Point of
T ;
A90:
dist (
u2cf2n,
(f1 . ym))
< (e0 / 2) / 4
by A84, A88, TOPMETR:def 1;
i in Seg (len PS)
by A25, A82, FINSEQ_1:def 3;
then
g0 . ys in Ball (
((U2 * (canFS BM02)) /. (sigm . i)),
((e0 / 2) / 4))
by A79;
then
g0 . ys in { y where y is Element of (T | URSTPS) : dist (((U2 * (canFS BM02)) /. (sigm . i)),y) < (e0 / 2) / 4 }
by METRIC_1:def 14;
then A91:
ex
y being
Element of
(T | URSTPS) st
(
g0 . ys = y &
dist (
((U2 * (canFS BM02)) /. (sigm . i)),
y)
< (e0 / 2) / 4 )
;
then reconsider g0ys =
g0 . ys as
Point of
(T | URSTPS) ;
reconsider g0ysm =
g0ys as
Point of
T ;
reconsider g0ysn =
g0ysm as
Point of
T ;
A93:
dist (
u2cf2n,
(g1 . ym))
< (e0 / 2) / 4
by A84, A91, TOPMETR:def 1;
A94:
dist (
u2cf2n,
(f1 . xm))
<= (dist (u2cf2n,(f1 . ym))) + (dist ((f1 . ym),(f1 . xm)))
by METRIC_1:4;
(dist (u2cf2n,(f1 . ym))) + (dist ((f1 . ym),(f1 . xm))) < ((e0 / 2) / 4) + ((e0 / 2) / 4)
by A86, A90, XREAL_1:8;
then A95:
dist (
u2cf2n,
(f1 . xm))
< (e0 / 2) / 2
by XXREAL_0:2, A94;
A96:
dist (
u2cf2n,
(g1 . xm))
<= (dist (u2cf2n,(g1 . ym))) + (dist ((g1 . ym),(g1 . xm)))
by METRIC_1:4;
(dist (u2cf2n,(g1 . ym))) + (dist ((g1 . ym),(g1 . xm))) < ((e0 / 2) / 4) + ((e0 / 2) / 4)
by A87, A93, XREAL_1:8;
then A97:
dist (
u2cf2n,
(g1 . xm))
< (e0 / 2) / 2
by XXREAL_0:2, A96;
A98:
dist (
(f1 . xm),
(g1 . xm))
<= (dist (u2cf2n,(f1 . xm))) + (dist (u2cf2n,(g1 . xm)))
by METRIC_1:4;
(dist (u2cf2n,(f1 . xm))) + (dist (u2cf2n,(g1 . xm))) < ((e0 / 2) / 2) + ((e0 / 2) / 2)
by A95, A97, XREAL_1:8;
hence
dist (
(f0 . x),
(g0 . x))
<= e0 / 2
by XXREAL_0:2, A98;
verum
end;
reconsider f1 =
f,
g1 =
g as
Point of
(MetricSpace_of_ContinuousFunctions (S,T)) by TOPMETR:def 1, TARSKI:def 3;
dist (
f1,
g1)
<= e0 / 2
by A80, Th12;
then
dist (
f,
g)
<= e0 / 2
by TOPMETR:def 1;
hence
dist (
f,
g)
< e0
by A8, XXREAL_0:2;
verum
end;
A99:
for
f being
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) ex
sigm being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) st
f in BST . sigm
proof
let f be
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H);
ex sigm being Function of (Seg (len PS)),(Seg (len (canFS BM02))) st f in BST . sigm
f in H
by A3;
then
f in MetricSpace_of_ContinuousFunctions (
S,
T)
;
then
ex
g being
Function of
S,
(TopSpaceMetr T) st
(
f = g &
g is
continuous )
;
then reconsider g =
f as
Function of the
carrier of
S, the
carrier of
T ;
defpred S5[
object ,
object ]
means ex
i,
j being
Nat st
(
i = $1 &
j = $2 &
g . (PS /. i) in Ball (
((U2 * (canFS BM02)) /. j),
((e0 / 2) / 4)) );
A100:
for
x being
object st
x in Seg (len PS) holds
ex
y being
object st
(
y in Seg (len (canFS BM02)) &
S5[
x,
y] )
proof
let x be
object ;
( x in Seg (len PS) implies ex y being object st
( y in Seg (len (canFS BM02)) & S5[x,y] ) )
assume A101:
x in Seg (len PS)
;
ex y being object st
( y in Seg (len (canFS BM02)) & S5[x,y] )
then reconsider i =
x as
Nat ;
A102:
i in dom PS
by A101, FINSEQ_1:def 3;
consider NHx,
CHx being non
empty Subset of
T such that A103:
(
NHx = { (f . (PS /. i)) where f is Function of S,T : f in H } &
STPS /. i = Cl NHx )
by A39, A102, A24, A38;
A104:
g . (PS /. i) in NHx
by A103, A3;
NHx c= Cl NHx
by Th1;
then A105:
g . (PS /. i) in STPS /. i
by A104, A103;
A107:
g . (PS /. i) in STPS . i
by A105, PARTFUN1:def 6, A102, A24, A38;
STPS . i in rng STPS
by A102, A24, A38, FUNCT_1:3;
then
g . (PS /. i) in URSTPS
by A107, TARSKI:def 4;
then
g . (PS /. i) in the
carrier of
(T | URSTPS)
by TOPMETR:def 2;
then consider V being
set such that A108:
(
g . (PS /. i) in V &
V in rng (canFS BM02) )
by A70, TARSKI:def 4;
consider j being
object such that A109:
(
j in dom (canFS BM02) &
V = (canFS BM02) . j )
by A108, FUNCT_1:def 3;
A110:
j in Seg (card BM02)
by A62, FINSEQ_1:def 3, A109;
reconsider j =
j as
Nat by A109;
A111:
(canFS BM02) . j = Ball (
((U2 * (canFS BM02)) /. j),
((e0 / 2) / 4))
by A67, A65, A110;
j in Seg (len (canFS BM02))
by FINSEQ_1:def 3, A109;
hence
ex
y being
object st
(
y in Seg (len (canFS BM02)) &
S5[
x,
y] )
by A108, A109, A111;
verum
end;
consider sigm being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) such that A112:
for
x being
object st
x in Seg (len PS) holds
S5[
x,
sigm . x]
from FUNCT_2:sch 1(A100);
A113:
for
i being
Nat st
i in Seg (len PS) holds
g . (PS /. i) in Ball (
((U2 * (canFS BM02)) /. (sigm . i)),
((e0 / 2) / 4))
A114:
BST . sigm = { f where f is Function of S,T : ( f in (MetricSpace_of_ContinuousFunctions (S,T)) | H & ( for i being Nat st i in Seg (len PS) holds
f . (PS /. i) in Ball (((U2 * (canFS BM02)) /. (sigm . i)),((e0 / 2) / 4)) ) ) }
by A73;
take
sigm
;
f in BST . sigm
g in (MetricSpace_of_ContinuousFunctions (S,T)) | H
;
hence
f in BST . sigm
by A114, A113;
verum
end;
A115:
for
sigm being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) ex
f being
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
BST . sigm c= Ball (
f,
e0)
proof
let sigm be
Function of
(Seg (len PS)),
(Seg (len (canFS BM02)));
ex f being Point of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st BST . sigm c= Ball (f,e0)
per cases
( BST . sigm = {} or BST . sigm <> {} )
;
suppose
BST . sigm <> {}
;
ex f being Point of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st BST . sigm c= Ball (f,e0)then consider f being
object such that A117:
f in BST . sigm
by XBOOLE_0:def 1;
sigm in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02))))
by A55, FUNCT_2:8;
then A118:
BST . sigm in bool the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H)
by FUNCT_2:5;
then reconsider f =
f as
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) by A117;
take
f
;
BST . sigm c= Ball (f,e0)let z be
object ;
TARSKI:def 3 ( not z in BST . sigm or z in Ball (f,e0) )assume A119:
z in BST . sigm
;
z in Ball (f,e0)then reconsider g =
z as
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) by A118;
dist (
f,
g)
< e0
by A117, A119, A75;
then
g in { y where y is Point of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) : dist (f,y) < e0 }
;
hence
z in Ball (
f,
e0)
by METRIC_1:def 14;
verum end; end;
end;
defpred S5[
object ,
object ]
means ex
f being
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
(
BST . $1
c= Ball (
f,
e0) & $2
= Ball (
f,
e0) );
A120:
for
z being
object st
z in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02)))) holds
ex
f being
object st
(
f in bool the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) &
S5[
z,
f] )
proof
let z be
object ;
( z in Funcs ((Seg (len PS)),(Seg (len (canFS BM02)))) implies ex f being object st
( f in bool the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) & S5[z,f] ) )
assume
z in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02))))
;
ex f being object st
( f in bool the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) & S5[z,f] )
then reconsider sigm =
z as
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) by FUNCT_2:66;
ex
f being
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
BST . sigm c= Ball (
f,
e0)
by A115;
hence
ex
f being
object st
(
f in bool the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) &
S5[
z,
f] )
;
verum
end;
consider FF being
Function of
(Funcs ((Seg (len PS)),(Seg (len (canFS BM02))))),
(bool the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H)) such that A121:
for
z being
object st
z in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02)))) holds
S5[
z,
FF . z]
from FUNCT_2:sch 1(A120);
A122:
dom FF = Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02))))
by FUNCT_2:def 1;
reconsider L =
rng FF as
finite set by A74;
reconsider L =
L as
Subset-Family of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) ;
take
L
;
( L is finite & the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) = union L & ( for C being Subset of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C in L holds
ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e0) ) )
thus
L is
finite
;
( the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) = union L & ( for C being Subset of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C in L holds
ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e0) ) )
the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) c= union L
proof
let f be
object ;
TARSKI:def 3 ( not f in the carrier of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) or f in union L )
assume
f in the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H)
;
f in union L
then reconsider g =
f as
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) ;
consider sigm being
Function of
(Seg (len PS)),
(Seg (len (canFS BM02))) such that A123:
g in BST . sigm
by A99;
A124:
sigm in Funcs (
(Seg (len PS)),
(Seg (len (canFS BM02))))
by A55, FUNCT_2:8;
then consider w being
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) such that A125:
(
BST . sigm c= Ball (
w,
e0) &
FF . sigm = Ball (
w,
e0) )
by A121;
FF . sigm in rng FF
by FUNCT_1:3, A124, A122;
hence
f in union L
by TARSKI:def 4, A123, A125;
verum
end;
hence
the
carrier of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) = union L
;
for C being Subset of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C in L holds
ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e0)
thus
for
C being
Subset of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
C in L holds
ex
w being
Element of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) st
C = Ball (
w,
e0)
verumproof
let C be
Subset of
((MetricSpace_of_ContinuousFunctions (S,T)) | H);
( C in L implies ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e0) )
assume
C in L
;
ex w being Element of ((MetricSpace_of_ContinuousFunctions (S,T)) | H) st C = Ball (w,e0)
then consider x being
object such that A126:
(
x in dom FF &
C = FF . x )
by FUNCT_1:def 3;
consider w being
Point of
((MetricSpace_of_ContinuousFunctions (S,T)) | H) such that A127:
(
BST . x c= Ball (
w,
e0) &
FF . x = Ball (
w,
e0) )
by A121, A126;
take
w
;
C = Ball (w,e0)
thus
C = Ball (
w,
e0)
by A126, A127;
verum
end;
end;
hence
(MetricSpace_of_ContinuousFunctions (S,T)) | H is totally_bounded
; verum