let T be non empty TopSpace; for F being Subset-Family of T
for S being SetSequence of T st rng S c= F & S is non-empty holds
ex R being non-empty closed SetSequence of T st
( R is non-ascending & ( F is locally_finite & S is one-to-one implies meet R = {} ) & ( for i being Nat ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } ) ) )
let F be Subset-Family of T; for S being SetSequence of T st rng S c= F & S is non-empty holds
ex R being non-empty closed SetSequence of T st
( R is non-ascending & ( F is locally_finite & S is one-to-one implies meet R = {} ) & ( for i being Nat ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } ) ) )
let S be SetSequence of T; ( rng S c= F & S is non-empty implies ex R being non-empty closed SetSequence of T st
( R is non-ascending & ( F is locally_finite & S is one-to-one implies meet R = {} ) & ( for i being Nat ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } ) ) ) )
assume that
A1:
rng S c= F
and
A2:
S is non-empty
; ex R being non-empty closed SetSequence of T st
( R is non-ascending & ( F is locally_finite & S is one-to-one implies meet R = {} ) & ( for i being Nat ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } ) ) )
defpred S1[ object , object ] means for i being Nat st i = $1 holds
ex SS being Subset-Family of T st
( SS c= F & SS = { (S . j) where j is Element of NAT : j >= i } & $2 = Cl (union SS) );
A3:
for x being object st x in NAT holds
ex y being object st
( y in bool the carrier of T & S1[x,y] )
consider R being SetSequence of T such that
A5:
for x being object st x in NAT holds
S1[x,R . x]
from FUNCT_2:sch 1(A3);
then reconsider R = R as non-empty closed SetSequence of T by A6, Def6, FUNCT_1:def 9;
take
R
; ( R is non-ascending & ( F is locally_finite & S is one-to-one implies meet R = {} ) & ( for i being Nat ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } ) ) )
hence
R is non-ascending
by KURATO_0:def 3; ( ( F is locally_finite & S is one-to-one implies meet R = {} ) & ( for i being Nat ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } ) ) )
thus
( F is locally_finite & S is one-to-one implies meet R = {} )
for i being Nat ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } )proof
A18:
dom S = NAT
by FUNCT_2:def 1;
then reconsider rngS =
rng S as non
empty Subset-Family of
T by RELAT_1:42;
reconsider Sp =
S as
sequence of
rngS by A18, FUNCT_2:1;
assume that A19:
F is
locally_finite
and A20:
S is
one-to-one
;
meet R = {}
reconsider S9 =
Sp " as
Function ;
reconsider S9 =
S9 as
Function of
rngS,
NAT by A20, FUNCT_2:25;
deffunc H1(
Element of
rngS)
-> Element of
NAT =
S9 . $1;
assume
meet R <> {}
;
contradiction
then consider x being
object such that A21:
x in meet R
by XBOOLE_0:def 1;
reconsider x =
x as
Point of
T by A21;
rng S is
locally_finite
by A1, A19, PCOMPS_1:9;
then consider W being
Subset of
T such that A22:
x in W
and A23:
W is
open
and A24:
{ V where V is Subset of T : ( V in rngS & V meets W ) } is
finite
;
set X =
{ V where V is Subset of T : ( V in rngS & V meets W ) } ;
set Y =
{ H1(z) where z is Element of rngS : z in { V where V is Subset of T : ( V in rngS & V meets W ) } } ;
A25:
{ H1(z) where z is Element of rngS : z in { V where V is Subset of T : ( V in rngS & V meets W ) } } is
finite
from FRAENKEL:sch 21(A24);
{ H1(z) where z is Element of rngS : z in { V where V is Subset of T : ( V in rngS & V meets W ) } } c= NAT
then reconsider Y =
{ H1(z) where z is Element of rngS : z in { V where V is Subset of T : ( V in rngS & V meets W ) } } as
Subset of
NAT ;
consider n being
Nat such that A26:
for
k being
Nat st
k in Y holds
k <= n
by A25, STIRL2_1:56;
set n1 =
n + 1;
A27:
x in R . (n + 1)
by A21, KURATO_0:3;
consider Sn being
Subset-Family of
T such that A28:
Sn c= F
and A29:
Sn = { (S . j) where j is Element of NAT : j >= n + 1 }
and A30:
R . (n + 1) = Cl (union Sn)
by A5;
Cl (union Sn) = union (clf Sn)
by A19, A28, PCOMPS_1:9, PCOMPS_1:20;
then consider CLF being
set such that A31:
x in CLF
and A32:
CLF in clf Sn
by A30, A27, TARSKI:def 4;
reconsider CLF =
CLF as
Subset of
T by A32;
consider U being
Subset of
T such that A33:
CLF = Cl U
and A34:
U in Sn
by A32, PCOMPS_1:def 2;
consider j being
Element of
NAT such that A35:
U = S . j
and A36:
j >= n + 1
by A29, A34;
A37:
Sp . j in rngS
;
Sp . j meets W
by A22, A23, A31, A33, A35, TOPS_1:12;
then A38:
Sp . j in { V where V is Subset of T : ( V in rngS & V meets W ) }
by A37;
(S ") . (S . j) = j
by A20, FUNCT_2:26;
then
j in Y
by A38;
then
j <= n
by A26;
hence
contradiction
by A36, NAT_1:13;
verum
end;
let i be Nat; ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } )
i in NAT
by ORDINAL1:def 12;
then
ex SS being Subset-Family of T st
( SS c= F & SS = { (S . j) where j is Element of NAT : j >= i } & R . i = Cl (union SS) )
by A5;
hence
ex Si being Subset-Family of T st
( R . i = Cl (union Si) & Si = { (S . j) where j is Element of NAT : j >= i } )
; verum