let X, Y be non empty TopSpace; for S being Scott TopAugmentation of InclPoset the topology of Y
for f being Function of X,S st *graph f is open Subset of [:X,Y:] holds
f is continuous
let S be Scott TopAugmentation of InclPoset the topology of Y; for f being Function of X,S st *graph f is open Subset of [:X,Y:] holds
f is continuous
let f be Function of X,S; ( *graph f is open Subset of [:X,Y:] implies f is continuous )
A1:
RelStr(# the carrier of S, the InternalRel of S #) = RelStr(# the carrier of (InclPoset the topology of Y), the InternalRel of (InclPoset the topology of Y) #)
by YELLOW_9:def 4;
A2:
dom f = the carrier of X
by FUNCT_2:def 1;
assume
*graph f is open Subset of [:X,Y:]
; f is continuous
then consider AA being Subset-Family of [:X,Y:] such that
A3:
*graph f = union AA
and
A4:
for e being set st e in AA holds
ex X1 being Subset of X ex Y1 being Subset of Y st
( e = [:X1,Y1:] & X1 is open & Y1 is open )
by BORSUK_1:5;
A5:
the carrier of (InclPoset the topology of Y) = the topology of Y
by YELLOW_1:1;
A6:
now for P being Subset of S st P is open holds
f " P is open let P be
Subset of
S;
( P is open implies f " P is open )assume A7:
P is
open
;
f " P is open now for x being set holds
( ( x in f " P implies ex Q being Subset of X st
( Q is open & Q c= f " P & x in Q ) ) & ( ex Q being Subset of X st
( Q is open & Q c= f " P & x in Q ) implies x in f " P ) )let x be
set ;
( ( x in f " P implies ex Q being Subset of X st
( Q is open & Q c= f " P & x in Q ) ) & ( ex Q being Subset of X st
( Q is open & Q c= f " P & x in Q ) implies x in f " P ) )hereby ( ex Q being Subset of X st
( Q is open & Q c= f " P & x in Q ) implies x in f " P )
defpred S1[
object ,
object ]
means (
x in $2
`1 & $1
in $2
`2 &
[:($2 `1),($2 `2):] c= *graph f );
assume A8:
x in f " P
;
ex Q being Subset of X st
( Q is open & Q c= f " P & x in Q )then reconsider y =
x as
Element of
X ;
A9:
now for e being object st e in f . x holds
ex u being object st
( u in [: the topology of X, the topology of Y:] & S1[e,u] )let e be
object ;
( e in f . x implies ex u being object st
( u in [: the topology of X, the topology of Y:] & S1[e,u] ) )assume
e in f . x
;
ex u being object st
( u in [: the topology of X, the topology of Y:] & S1[e,u] )then
[x,e] in *graph f
by A2, A8, Th38;
then consider V being
set such that A10:
[x,e] in V
and A11:
V in AA
by A3, TARSKI:def 4;
consider A being
Subset of
X,
B being
Subset of
Y such that A12:
V = [:A,B:]
and A13:
(
A is
open &
B is
open )
by A4, A11;
reconsider u =
[A,B] as
object ;
take u =
u;
( u in [: the topology of X, the topology of Y:] & S1[e,u] )
(
A in the
topology of
X &
B in the
topology of
Y )
by A13, PRE_TOPC:def 2;
hence
u in [: the topology of X, the topology of Y:]
by ZFMISC_1:87;
S1[e,u]thus
S1[
e,
u]
by A3, A10, A11, A12, ZFMISC_1:74, ZFMISC_1:87;
verum end; consider g being
Function such that A14:
(
dom g = f . x &
rng g c= [: the topology of X, the topology of Y:] )
and A15:
for
a being
object st
a in f . x holds
S1[
a,
g . a]
from FUNCT_1:sch 6(A9);
set J =
{ (union A) where A is Subset of (proj2 (rng g)) : A is finite } ;
A16:
proj2 (rng g) c= the
topology of
Y
by A14, FUNCT_5:11;
A17:
{ (union A) where A is Subset of (proj2 (rng g)) : A is finite } c= the
topology of
Y
{} (proj2 (rng g)) in { (union A) where A is Subset of (proj2 (rng g)) : A is finite }
by ZFMISC_1:2;
then reconsider J =
{ (union A) where A is Subset of (proj2 (rng g)) : A is finite } as non
empty Subset of
(InclPoset the topology of Y) by A17, YELLOW_1:1;
J is
directed
then reconsider J9 =
J as non
empty directed Subset of
S by A1, WAYBEL_0:3;
A25:
proj2 (rng g) c= bool (f . x)
proof
let z be
object ;
TARSKI:def 3 ( not z in proj2 (rng g) or z in bool (f . x) )
reconsider zz =
z as
set by TARSKI:1;
assume
z in proj2 (rng g)
;
z in bool (f . x)
then consider z1 being
object such that A26:
[z1,z] in rng g
by XTUPLE_0:def 13;
A27:
[z1,z] `1 = z1
;
reconsider zz1 =
z1 as
set by TARSKI:1;
A28:
ex
a being
object st
(
a in dom g &
[z1,z] = g . a )
by A26, FUNCT_1:def 3;
then A29:
x in zz1
by A14, A15, A27;
[z1,z] `2 = z
;
then A30:
[:zz1,zz:] c= *graph f
by A14, A15, A28, A27;
zz c= f . x
hence
z in bool (f . x)
;
verum
end;
union J = f . y
then
sup J = f . y
by YELLOW_1:22;
then A37:
sup J9 = f . y
by A1, YELLOW_0:17, YELLOW_0:26;
f . y in the
topology of
Y
by A5, A1;
then reconsider W =
f . y as
open Subset of
Y by PRE_TOPC:def 2;
A38:
proj1 (rng g) c= the
topology of
X
by A14, FUNCT_5:11;
defpred S2[
object ,
object ]
means ex
c1,
d being
set st
(
d = $1 &
[c1,$1] = g . $2 &
x in c1 & $2
in d & $2
in f . x &
[:c1,d:] c= *graph f );
f . x in P
by A8, FUNCT_2:38;
then
J meets P
by A7, A37, WAYBEL11:def 1;
then consider a being
object such that A39:
a in J
and A40:
a in P
by XBOOLE_0:3;
reconsider a =
a as
Element of
S by A40;
consider A being
Subset of
(proj2 (rng g)) such that A41:
a = union A
and A42:
A is
finite
by A39;
A43:
now for c being object st c in A holds
ex a being object st
( a in W & S2[c,a] )let c be
object ;
( c in A implies ex a being object st
( a in W & S2[c,a] ) )assume
c in A
;
ex a being object st
( a in W & S2[c,a] )then consider c1 being
object such that A44:
[c1,c] in rng g
by XTUPLE_0:def 13;
reconsider cc1 =
c1 as
set by TARSKI:1;
consider a being
object such that A45:
a in dom g
and A46:
[c1,c] = g . a
by A44, FUNCT_1:def 3;
reconsider cc =
c as
set by TARSKI:1;
reconsider a =
a as
object ;
take a =
a;
( a in W & S2[c,a] )thus
a in W
by A14, A45;
S2[c,a]A47:
[c1,c] `1 = c1
;
then A48:
x in cc1
by A14, A15, A45, A46;
A49:
[c1,c] `2 = c
;
then
[:cc1,cc:] c= *graph f
by A14, A15, A45, A46, A47;
hence
S2[
c,
a]
by A14, A15, A45, A46, A49, A48;
verum end; consider hh being
Function such that A50:
(
dom hh = A &
rng hh c= W )
and A51:
for
c being
object st
c in A holds
S2[
c,
hh . c]
from FUNCT_1:sch 6(A43);
set B =
proj1 (g .: (rng hh));
g .: (rng hh) c= rng g
by RELAT_1:111;
then
proj1 (g .: (rng hh)) c= proj1 (rng g)
by XTUPLE_0:8;
then A52:
proj1 (g .: (rng hh)) c= the
topology of
X
by A38;
then reconsider B =
proj1 (g .: (rng hh)) as
Subset-Family of
X by XBOOLE_1:1;
reconsider B =
B as
Subset-Family of
X ;
reconsider Q =
Intersect B as
Subset of
X ;
take Q =
Q;
( Q is open & Q c= f " P & x in Q )
g .: (rng hh) is
finite
by A42, A50, FINSET_1:5, FINSET_1:8;
then
B is
finite
by Th39;
then
Q in FinMeetCl the
topology of
X
by A52, CANTOR_1:def 3;
then
Q in the
topology of
X
by CANTOR_1:5;
hence
Q is
open
by PRE_TOPC:def 2;
( Q c= f " P & x in Q )thus
Q c= f " P
x in Qproof
let z be
object ;
TARSKI:def 3 ( not z in Q or z in f " P )
assume A53:
z in Q
;
z in f " P
then reconsider zz =
z as
Element of
X ;
reconsider fz =
f . zz,
aa =
a as
Element of
(InclPoset the topology of Y) by A1;
a c= f . zz
proof
let p be
object ;
TARSKI:def 3 ( not p in a or p in f . zz )
assume
p in a
;
p in f . zz
then consider q being
set such that A54:
p in q
and A55:
q in A
by A41, TARSKI:def 4;
S2[
q,
hh . q]
by A51, A55;
then consider q1,
d being
set such that A56:
d = q
and A57:
[q1,q] = g . (hh . q)
and A58:
hh . q in f . x
and A59:
[:q1,d:] c= *graph f
;
hh . q in rng hh
by A50, A55, FUNCT_1:def 3;
then
[q1,q] in g .: (rng hh)
by A14, A57, A58, FUNCT_1:def 6;
then
q1 in B
by XTUPLE_0:def 12;
then
zz in q1
by A53, SETFAM_1:43;
then
[zz,p] in [:q1,q:]
by A54, ZFMISC_1:87;
hence
p in f . zz
by A59, Th38, A56;
verum
end;
then
aa <= fz
by YELLOW_1:3;
then
a <= f . zz
by A1, YELLOW_0:1;
then
f . zz in P
by A7, A40, WAYBEL_0:def 20;
hence
z in f " P
by FUNCT_2:38;
verum
end; now for c1 being set st c1 in B holds
x in c1let c1 be
set ;
( c1 in B implies x in c1 )assume
c1 in B
;
x in c1then consider c being
object such that A60:
[c1,c] in g .: (rng hh)
by XTUPLE_0:def 12;
consider b being
object such that
b in dom g
and A61:
b in rng hh
and A62:
[c1,c] = g . b
by A60, FUNCT_1:def 6;
consider c9 being
object such that A63:
c9 in dom hh
and A64:
b = hh . c9
by A61, FUNCT_1:def 3;
ex
c91,
d being
set st
(
d = c9 &
[c91,c9] = g . (hh . c9) &
x in c91 &
hh . c9 in d &
hh . c9 in f . x &
[:c91,d:] c= *graph f )
by A50, A51, A63;
hence
x in c1
by A62, A64, XTUPLE_0:1;
verum end; hence
x in Q
by A8, SETFAM_1:43;
verum
end; assume
ex
Q being
Subset of
X st
(
Q is
open &
Q c= f " P &
x in Q )
;
x in f " Phence
x in f " P
;
verum end; hence
f " P is
open
by TOPS_1:25;
verum end;
[#] S <> {}
;
hence
f is continuous
by A6, TOPS_2:43; verum