defpred S1[ set ] means verum;
let I be non empty set ; for J being non-Empty TopStruct-yielding ManySortedSet of I
for i being Element of I
for F being Subset of (product_prebasis J) st ( for i being Element of I holds J . i is compact ) & ( for G being finite Subset of F holds not [#] (product J) c= union G ) holds
ex xi being Element of (J . i) st
for G being finite Subset of F holds not (proj (J,i)) " {xi} c= union G
let J be non-Empty TopStruct-yielding ManySortedSet of I; for i being Element of I
for F being Subset of (product_prebasis J) st ( for i being Element of I holds J . i is compact ) & ( for G being finite Subset of F holds not [#] (product J) c= union G ) holds
ex xi being Element of (J . i) st
for G being finite Subset of F holds not (proj (J,i)) " {xi} c= union G
let i be Element of I; for F being Subset of (product_prebasis J) st ( for i being Element of I holds J . i is compact ) & ( for G being finite Subset of F holds not [#] (product J) c= union G ) holds
ex xi being Element of (J . i) st
for G being finite Subset of F holds not (proj (J,i)) " {xi} c= union G
let F be Subset of (product_prebasis J); ( ( for i being Element of I holds J . i is compact ) & ( for G being finite Subset of F holds not [#] (product J) c= union G ) implies ex xi being Element of (J . i) st
for G being finite Subset of F holds not (proj (J,i)) " {xi} c= union G )
assume that
A1:
for i being Element of I holds J . i is compact
and
A2:
for G being finite Subset of F holds not [#] (product J) c= union G
; ex xi being Element of (J . i) st
for G being finite Subset of F holds not (proj (J,i)) " {xi} c= union G
deffunc H1( set ) -> Element of bool the carrier of (product J) = (proj (J,i)) " $1;
defpred S2[ object , object ] means ex A being set st
( A = $2 & $1 in A & (proj (J,i)) " A in F & ( for V being Subset of (J . i) st V = $2 holds
V is open ) );
assume A3:
for xi being Element of (J . i) ex G being finite Subset of F st (proj (J,i)) " {xi} c= union G
; contradiction
A4:
for xi being object st xi in the carrier of (J . i) holds
ex Ai being object st
( Ai in bool the carrier of (J . i) & S2[xi,Ai] )
proof
let xi be
object ;
( xi in the carrier of (J . i) implies ex Ai being object st
( Ai in bool the carrier of (J . i) & S2[xi,Ai] ) )
assume
xi in the
carrier of
(J . i)
;
ex Ai being object st
( Ai in bool the carrier of (J . i) & S2[xi,Ai] )
then reconsider xi9 =
xi as
Element of
(J . i) ;
consider G being
finite Subset of
F such that A5:
(proj (J,i)) " {xi9} c= union G
by A3;
consider Ai being
Subset of
(J . i) such that
Ai <> [#] (J . i)
and A6:
xi in Ai
and A7:
(proj (J,i)) " Ai in G
and A8:
Ai is
open
by A2, A5, Th21;
take
Ai
;
( Ai in bool the carrier of (J . i) & S2[xi,Ai] )
thus
Ai in bool the
carrier of
(J . i)
;
S2[xi,Ai]
take
Ai
;
( Ai = Ai & xi in Ai & (proj (J,i)) " Ai in F & ( for V being Subset of (J . i) st V = Ai holds
V is open ) )
thus
Ai = Ai
;
( xi in Ai & (proj (J,i)) " Ai in F & ( for V being Subset of (J . i) st V = Ai holds
V is open ) )
thus
xi in Ai
by A6;
( (proj (J,i)) " Ai in F & ( for V being Subset of (J . i) st V = Ai holds
V is open ) )
thus
(proj (J,i)) " Ai in F
by A7;
for V being Subset of (J . i) st V = Ai holds
V is open
let V be
Subset of
(J . i);
( V = Ai implies V is open )
assume
V = Ai
;
V is open
hence
V is
open
by A8;
verum
end;
consider h being Function such that
A9:
dom h = the carrier of (J . i)
and
A10:
rng h c= bool the carrier of (J . i)
and
A11:
for xi being object st xi in the carrier of (J . i) holds
S2[xi,h . xi]
from FUNCT_1:sch 6(A4);
reconsider bGip = rng h as Subset-Family of (J . i) by A10;
reconsider bGip = bGip as Subset-Family of (J . i) ;
A12:
[#] (J . i) c= union bGip
for P being Subset of (J . i) st P in bGip holds
P is open
then A16:
bGip is open
by TOPS_2:def 1;
J . i is compact
by A1;
then consider Gip being Subset-Family of (J . i) such that
A17:
Gip c= bGip
and
A18:
[#] (J . i) c= union Gip
and
A19:
Gip is finite
by A12, A16, Th14;
reconsider Gip = Gip as non empty finite Subset-Family of (J . i) by A18, A19, ZFMISC_1:2;
set Gp = { H1(Ai) where Ai is Element of Gip : S1[Ai] } ;
A20:
{ H1(Ai) where Ai is Element of Gip : S1[Ai] } c= F
{ H1(Ai) where Ai is Element of Gip : S1[Ai] } is finite
from PRE_CIRC:sch 1();
then reconsider Gp = { H1(Ai) where Ai is Element of Gip : S1[Ai] } as finite Subset of F by A20;
[#] (product J) c= union Gp
by A18, Th18;
hence
contradiction
by A2; verum