:: TEX_4 semantic presentation

begin

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( non empty ) ( non empty ) Subset of ) ;
cluster Cl A : ( ( non empty ) ( non empty ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( closed ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) -> non empty ;
end;

registration
let X be ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) ;
let A be ( ( empty ) ( empty trivial open closed boundary nowhere_dense ) Subset of ) ;
cluster Cl A : ( ( empty ) ( empty trivial open closed boundary nowhere_dense ) Element of bool the carrier of X : ( ( TopSpace-like ) ( TopSpace-like ) TopStruct ) : ( ( ) ( ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( closed ) Element of bool the carrier of X : ( ( TopSpace-like ) ( TopSpace-like ) TopStruct ) : ( ( ) ( ) set ) : ( ( ) ( non empty ) set ) ) -> empty ;
end;

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( non proper ) ( non empty non proper ) Subset of ) ;
cluster Cl A : ( ( non proper ) ( non empty non proper ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) -> non proper ;
end;

registration
let X be ( ( non trivial TopSpace-like ) ( non empty non trivial TopSpace-like ) TopSpace) ;
let A be ( ( non trivial ) ( non empty non trivial ) Subset of ) ;
cluster Cl A : ( ( non trivial ) ( non empty non trivial ) Element of bool the carrier of X : ( ( non trivial TopSpace-like ) ( non empty non trivial TopSpace-like ) TopStruct ) : ( ( ) ( non empty non trivial ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of X : ( ( non trivial TopSpace-like ) ( non empty non trivial TopSpace-like ) TopStruct ) : ( ( ) ( non empty non trivial ) set ) : ( ( ) ( non empty ) set ) ) -> non trivial ;
end;

theorem :: TEX_4:1
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = meet { F : ( ( ) ( ) Subset of ) where F is ( ( ) ( ) Subset of ) : ( F : ( ( ) ( ) Subset of ) is closed & A : ( ( ) ( ) Subset of ) c= F : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

theorem :: TEX_4:2
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = meet { F : ( ( ) ( ) Subset of ) where F is ( ( ) ( ) Subset of ) : ( F : ( ( ) ( ) Subset of ) is closed & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in F : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( non proper ) ( non empty non proper ) Subset of ) ;
cluster Int A : ( ( non proper ) ( non empty non proper ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( open ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) -> non proper ;
end;

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( proper ) ( proper ) Subset of ) ;
cluster Int A : ( ( proper ) ( proper ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( open ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) -> proper ;
end;

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( empty ) ( empty trivial proper open closed boundary nowhere_dense ) Subset of ) ;
cluster Int A : ( ( empty ) ( empty trivial proper open closed boundary nowhere_dense ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( empty trivial proper open closed boundary nowhere_dense ) Element of bool the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) -> empty ;
end;

theorem :: TEX_4:3
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds Int A : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = union { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & G : ( ( ) ( ) Subset of ) c= A : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

begin

definition
let Y be ( ( ) ( ) TopStruct ) ;
let IT be ( ( ) ( ) Subset of ) ;
attr IT is anti-discrete means :: TEX_4:def 1
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) )
for G being ( ( ) ( ) Subset of ) st G : ( ( ) ( ) Subset of ) is open & x : ( ( ) ( ) Point of ( ( ) ( ) set ) ) in G : ( ( ) ( ) Subset of ) & x : ( ( ) ( ) Point of ( ( ) ( ) set ) ) in IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) holds
IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) c= G : ( ( ) ( ) Subset of ) ;
end;

definition
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is anti-discrete means :: TEX_4:def 2
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) )
for F being ( ( ) ( ) Subset of ) st F : ( ( ) ( ) Subset of ) is closed & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in F : ( ( ) ( ) Subset of ) & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) holds
A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) c= F : ( ( ) ( ) Subset of ) ;
end;

definition
let Y be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is anti-discrete means :: TEX_4:def 3
for G being ( ( ) ( ) Subset of ) holds
( not G : ( ( ) ( ) Subset of ) is open or A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) misses G : ( ( ) ( ) Subset of ) or A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) c= G : ( ( ) ( ) Subset of ) );
end;

definition
let Y be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is anti-discrete means :: TEX_4:def 4
for F being ( ( ) ( ) Subset of ) holds
( not F : ( ( ) ( ) Subset of ) is closed or A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) misses F : ( ( ) ( ) Subset of ) or A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) c= F : ( ( ) ( ) Subset of ) );
end;

theorem :: TEX_4:4
for Y0, Y1 being ( ( ) ( ) TopStruct )
for D0 being ( ( ) ( ) Subset of )
for D1 being ( ( ) ( ) Subset of ) st TopStruct(# the carrier of Y0 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of Y0 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of bool (bool the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) = TopStruct(# the carrier of Y1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of Y1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of bool (bool the carrier of b2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( strict ) TopStruct ) & D0 : ( ( ) ( ) Subset of ) = D1 : ( ( ) ( ) Subset of ) & D0 : ( ( ) ( ) Subset of ) is anti-discrete holds
D1 : ( ( ) ( ) Subset of ) is anti-discrete ;

theorem :: TEX_4:5
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( ) ( ) Subset of ) st B : ( ( ) ( ) Subset of ) c= A : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) is anti-discrete holds
B : ( ( ) ( ) Subset of ) is anti-discrete ;

theorem :: TEX_4:6
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) is anti-discrete ;

theorem :: TEX_4:7
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( empty ) ( empty trivial proper boundary ) Subset of ) holds A : ( ( empty ) ( empty trivial proper boundary ) Subset of ) is anti-discrete ;

definition
let Y be ( ( ) ( ) TopStruct ) ;
let IT be ( ( ) ( ) Subset-Family of ) ;
attr IT is anti-discrete-set-family means :: TEX_4:def 5
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) in IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) holds
A : ( ( ) ( ) Subset of ) is anti-discrete ;
end;

theorem :: TEX_4:8
for Y being ( ( non empty ) ( non empty ) TopStruct )
for F being ( ( ) ( ) Subset-Family of ) st F : ( ( ) ( ) Subset-Family of ) is anti-discrete-set-family & meet F : ( ( ) ( ) Subset-Family of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) <> {} : ( ( ) ( empty trivial ) set ) holds
union F : ( ( ) ( ) Subset-Family of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) is anti-discrete ;

theorem :: TEX_4:9
for Y being ( ( non empty ) ( non empty ) TopStruct )
for F being ( ( ) ( ) Subset-Family of ) st F : ( ( ) ( ) Subset-Family of ) is anti-discrete-set-family holds
meet F : ( ( ) ( ) Subset-Family of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) is anti-discrete ;

definition
let Y be ( ( ) ( ) TopStruct ) ;
let x be ( ( ) ( ) Point of ( ( ) ( ) set ) ) ;
func MaxADSF x -> ( ( ) ( ) Subset-Family of ) equals :: TEX_4:def 6
{ A : ( ( ) ( ) Subset of ) where A is ( ( ) ( ) Subset of ) : ( A : ( ( ) ( ) Subset of ) is anti-discrete & x : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) in A : ( ( ) ( ) Subset of ) ) } ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let x be ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ;
cluster MaxADSF x : ( ( ) ( ) Element of the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset-Family of ) -> non empty ;
end;

theorem :: TEX_4:10
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSF x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset-Family of ) is anti-discrete-set-family ;

theorem :: TEX_4:11
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = meet (MaxADSF x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( ) ( non empty ) Subset-Family of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:12
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) c= union (MaxADSF x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( ) ( non empty ) Subset-Family of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:13
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds union (MaxADSF x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( ) ( non empty ) Subset-Family of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) is anti-discrete ;

begin

definition
let Y be ( ( ) ( ) TopStruct ) ;
let IT be ( ( ) ( ) Subset of ) ;
attr IT is maximal_anti-discrete means :: TEX_4:def 7
( IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) is anti-discrete & ( for D being ( ( ) ( ) Subset of ) st D : ( ( ) ( ) Subset of ) is anti-discrete & IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) c= D : ( ( ) ( ) Subset of ) holds
IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) = D : ( ( ) ( ) Subset of ) ) );
end;

theorem :: TEX_4:14
for Y0, Y1 being ( ( ) ( ) TopStruct )
for D0 being ( ( ) ( ) Subset of )
for D1 being ( ( ) ( ) Subset of ) st TopStruct(# the carrier of Y0 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of Y0 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of bool (bool the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) = TopStruct(# the carrier of Y1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of Y1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of bool (bool the carrier of b2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( strict ) TopStruct ) & D0 : ( ( ) ( ) Subset of ) = D1 : ( ( ) ( ) Subset of ) & D0 : ( ( ) ( ) Subset of ) is maximal_anti-discrete holds
D1 : ( ( ) ( ) Subset of ) is maximal_anti-discrete ;

theorem :: TEX_4:15
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( empty ) ( empty trivial proper boundary ) Subset of ) holds not A : ( ( empty ) ( empty trivial proper boundary ) Subset of ) is maximal_anti-discrete ;

theorem :: TEX_4:16
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( non empty ) ( non empty ) Subset of ) st A : ( ( non empty ) ( non empty ) Subset of ) is anti-discrete & A : ( ( non empty ) ( non empty ) Subset of ) is open holds
A : ( ( non empty ) ( non empty ) Subset of ) is maximal_anti-discrete ;

theorem :: TEX_4:17
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( non empty ) ( non empty ) Subset of ) st A : ( ( non empty ) ( non empty ) Subset of ) is anti-discrete & A : ( ( non empty ) ( non empty ) Subset of ) is closed holds
A : ( ( non empty ) ( non empty ) Subset of ) is maximal_anti-discrete ;

definition
let Y be ( ( ) ( ) TopStruct ) ;
let x be ( ( ) ( ) Point of ( ( ) ( ) set ) ) ;
func MaxADSet x -> ( ( ) ( ) Subset of ) equals :: TEX_4:def 8
union (MaxADSF x : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) ) : ( ( ) ( ) Subset-Family of ) : ( ( ) ( ) Element of bool the carrier of Y : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let x be ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ;
cluster MaxADSet x : ( ( ) ( ) Element of the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) -> non empty ;
end;

theorem :: TEX_4:18
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) c= MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) ;

theorem :: TEX_4:19
for Y being ( ( non empty ) ( non empty ) TopStruct )
for D being ( ( ) ( ) Subset of )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st D : ( ( ) ( ) Subset of ) is anti-discrete & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in D : ( ( ) ( ) Subset of ) holds
D : ( ( ) ( ) Subset of ) c= MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) ;

theorem :: TEX_4:20
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) is maximal_anti-discrete ;

theorem :: TEX_4:21
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) iff MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) = MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) ) ;

theorem :: TEX_4:22
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) misses MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) or MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) = MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) ) ;

theorem :: TEX_4:23
for Y being ( ( non empty ) ( non empty ) TopStruct )
for F being ( ( ) ( ) Subset of )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st F : ( ( ) ( ) Subset of ) is closed & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in F : ( ( ) ( ) Subset of ) holds
MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= F : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:24
for Y being ( ( non empty ) ( non empty ) TopStruct )
for G being ( ( ) ( ) Subset of )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st G : ( ( ) ( ) Subset of ) is open & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in G : ( ( ) ( ) Subset of ) holds
MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= G : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:25
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= meet { F : ( ( ) ( ) Subset of ) where F is ( ( ) ( ) Subset of ) : ( F : ( ( ) ( ) Subset of ) is closed & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in F : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

theorem :: TEX_4:26
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in G : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

definition
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is maximal_anti-discrete means :: TEX_4:def 9
ex x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st
( x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) & A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) = MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) );
end;

theorem :: TEX_4:27
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( ) ( ) Subset of )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) is maximal_anti-discrete holds
A : ( ( ) ( ) Subset of ) = MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) ;

definition
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( non empty ) ( non empty ) Subset of ) ;
redefine attr A is maximal_anti-discrete means :: TEX_4:def 10
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) holds
A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) = MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) ;
end;

definition
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
func MaxADSet A -> ( ( ) ( ) Subset of ) equals :: TEX_4:def 11
union { (MaxADSet a : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( ) ( ) Subset of ) where a is ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : a : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) } : ( ( ) ( ) set ) ;
end;

theorem :: TEX_4:28
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) = MaxADSet {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:29
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( ) ( ) Subset of )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) meets MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) holds
MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) meets A : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:30
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( ) ( ) Subset of )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) meets MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) holds
MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:31
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) holds
MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= MaxADSet B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:32
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( ) ( ) Subset of ) holds A : ( ( ) ( ) Subset of ) c= MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:33
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( ) ( ) Subset of ) holds MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) = MaxADSet (MaxADSet A : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:34
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= MaxADSet B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) holds
MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= MaxADSet B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:35
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( ) ( ) Subset of ) st B : ( ( ) ( ) Subset of ) c= MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) c= MaxADSet B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) holds
MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) = MaxADSet B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:36
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( ) ( ) Subset of ) holds MaxADSet (A : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) = (MaxADSet A : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) \/ (MaxADSet B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:37
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( ) ( ) Subset of ) holds MaxADSet (A : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) c= (MaxADSet A : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) /\ (MaxADSet B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( non empty ) ( non empty ) Subset of ) ;
cluster MaxADSet A : ( ( non empty ) ( non empty ) Element of bool the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) -> non empty ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( empty ) ( empty trivial proper boundary ) Subset of ) ;
cluster MaxADSet A : ( ( empty ) ( empty trivial proper boundary ) Element of bool the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) -> empty ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( non proper ) ( non empty non proper ) Subset of ) ;
cluster MaxADSet A : ( ( non proper ) ( non empty non proper ) Element of bool the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) -> non proper ;
end;

registration
let Y be ( ( non trivial ) ( non empty non trivial ) TopStruct ) ;
let A be ( ( non trivial ) ( non empty non trivial ) Subset of ) ;
cluster MaxADSet A : ( ( non trivial ) ( non empty non trivial ) Element of bool the carrier of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) : ( ( ) ( non empty non trivial ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) -> non trivial ;
end;

theorem :: TEX_4:38
for Y being ( ( non empty ) ( non empty ) TopStruct )
for G, A being ( ( ) ( ) Subset of ) st G : ( ( ) ( ) Subset of ) is open & A : ( ( ) ( ) Subset of ) c= G : ( ( ) ( ) Subset of ) holds
MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= G : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:39
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( ) ( ) Subset of ) st { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & A : ( ( ) ( ) Subset of ) c= G : ( ( ) ( ) Subset of ) ) } <> {} : ( ( ) ( empty trivial ) set ) holds
MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & A : ( ( ) ( ) Subset of ) c= G : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

theorem :: TEX_4:40
for Y being ( ( non empty ) ( non empty ) TopStruct )
for F, A being ( ( ) ( ) Subset of ) st F : ( ( ) ( ) Subset of ) is closed & A : ( ( ) ( ) Subset of ) c= F : ( ( ) ( ) Subset of ) holds
MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= F : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:41
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( ) ( ) Subset of ) st { F : ( ( ) ( ) Subset of ) where F is ( ( ) ( ) Subset of ) : ( F : ( ( ) ( ) Subset of ) is closed & A : ( ( ) ( ) Subset of ) c= F : ( ( ) ( ) Subset of ) ) } <> {} : ( ( ) ( empty trivial ) set ) holds
MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= meet { F : ( ( ) ( ) Subset of ) where F is ( ( ) ( ) Subset of ) : ( F : ( ( ) ( ) Subset of ) is closed & A : ( ( ) ( ) Subset of ) c= F : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

begin

definition
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is anti-discrete means :: TEX_4:def 12
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) holds
A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) c= Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;
end;

definition
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is anti-discrete means :: TEX_4:def 13
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) holds
Cl A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;
end;

definition
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is anti-discrete means :: TEX_4:def 14
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) & y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) holds
Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = Cl {y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;
end;

theorem :: TEX_4:42
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) )
for D being ( ( ) ( ) Subset of ) st D : ( ( ) ( ) Subset of ) is anti-discrete & Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) c= D : ( ( ) ( ) Subset of ) holds
D : ( ( ) ( ) Subset of ) = Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:43
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( ( A : ( ( ) ( ) Subset of ) is anti-discrete & A : ( ( ) ( ) Subset of ) is closed ) iff for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in A : ( ( ) ( ) Subset of ) holds
A : ( ( ) ( ) Subset of ) = Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ) ;

theorem :: TEX_4:44
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is anti-discrete & not A : ( ( ) ( ) Subset of ) is open holds
A : ( ( ) ( ) Subset of ) is boundary ;

theorem :: TEX_4:45
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) holds
{x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) is maximal_anti-discrete ;

theorem :: TEX_4:46
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in G : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

theorem :: TEX_4:47
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= meet { F : ( ( ) ( ) Subset of ) where F is ( ( ) ( ) Subset of ) : ( F : ( ( ) ( ) Subset of ) is closed & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in F : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

theorem :: TEX_4:48
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) c= Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:49
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) = MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) iff Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = Cl {y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ) ;

theorem :: TEX_4:50
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) misses MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) Subset of ) iff Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) <> Cl {y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ) ;

definition
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let x be ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ;
:: original: MaxADSet
redefine func MaxADSet x -> ( ( non empty ) ( non empty ) Subset of ) equals :: TEX_4:def 15
(Cl {x : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) /\ (meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & x : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) in G : ( ( ) ( ) Subset of ) ) } ) : ( ( ) ( ) set ) : ( ( ) ( ) Element of bool the carrier of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;
end;

theorem :: TEX_4:51
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) c= Cl {y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) iff meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in G : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) c= meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in G : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ) ;

theorem :: TEX_4:52
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) c= Cl {y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) iff MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) c= meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) in G : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ) ;

theorem :: TEX_4:53
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) misses MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) iff ( ex V being ( ( ) ( ) Subset of ) st
( V : ( ( ) ( ) Subset of ) is open & MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) c= V : ( ( ) ( ) Subset of ) & V : ( ( ) ( ) Subset of ) misses MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) ) or ex W being ( ( ) ( ) Subset of ) st
( W : ( ( ) ( ) Subset of ) is open & W : ( ( ) ( ) Subset of ) misses MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) & MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) c= W : ( ( ) ( ) Subset of ) ) ) ) ;

theorem :: TEX_4:54
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) misses MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) iff ( ex E being ( ( ) ( ) Subset of ) st
( E : ( ( ) ( ) Subset of ) is closed & MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) c= E : ( ( ) ( ) Subset of ) & E : ( ( ) ( ) Subset of ) misses MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) ) or ex F being ( ( ) ( ) Subset of ) st
( F : ( ( ) ( ) Subset of ) is closed & F : ( ( ) ( ) Subset of ) misses MaxADSet x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) & MaxADSet y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty ) ( non empty ) Subset of ) c= F : ( ( ) ( ) Subset of ) ) ) ) ;

theorem :: TEX_4:55
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= meet { G : ( ( ) ( ) Subset of ) where G is ( ( ) ( ) Subset of ) : ( G : ( ( ) ( ) Subset of ) is open & A : ( ( ) ( ) Subset of ) c= G : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

theorem :: TEX_4:56
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for P being ( ( ) ( ) Subset of ) st P : ( ( ) ( ) Subset of ) is open holds
MaxADSet P : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) = P : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:57
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds MaxADSet (Int A : ( ( ) ( ) Subset of ) ) : ( ( ) ( open ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) = Int A : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:58
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= meet { F : ( ( ) ( ) Subset of ) where F is ( ( ) ( ) Subset of ) : ( F : ( ( ) ( ) Subset of ) is closed & A : ( ( ) ( ) Subset of ) c= F : ( ( ) ( ) Subset of ) ) } : ( ( ) ( ) set ) ;

theorem :: TEX_4:59
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) c= Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:60
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for P being ( ( ) ( ) Subset of ) st P : ( ( ) ( ) Subset of ) is closed holds
MaxADSet P : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) = P : ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:61
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds MaxADSet (Cl A : ( ( ) ( ) Subset of ) ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) = Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:62
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds Cl (MaxADSet A : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:63
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st MaxADSet A : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) = MaxADSet B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Subset of ) holds
Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = Cl B : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:64
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for P, Q being ( ( ) ( ) Subset of ) st ( P : ( ( ) ( ) Subset of ) is closed or Q : ( ( ) ( ) Subset of ) is closed ) holds
MaxADSet (P : ( ( ) ( ) Subset of ) /\ Q : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) = (MaxADSet P : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) /\ (MaxADSet Q : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

theorem :: TEX_4:65
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for P, Q being ( ( ) ( ) Subset of ) st ( P : ( ( ) ( ) Subset of ) is open or Q : ( ( ) ( ) Subset of ) is open ) holds
MaxADSet (P : ( ( ) ( ) Subset of ) /\ Q : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) Subset of ) = (MaxADSet P : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) /\ (MaxADSet Q : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ;

begin

theorem :: TEX_4:66
for Y being ( ( non empty ) ( non empty ) TopStruct )
for Y0 being ( ( ) ( ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) )
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) = the carrier of Y0 : ( ( ) ( ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) set ) & Y0 : ( ( ) ( ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is anti-discrete holds
A : ( ( ) ( ) Subset of ) is anti-discrete ;

theorem :: TEX_4:67
for Y being ( ( non empty ) ( non empty ) TopStruct )
for Y0 being ( ( ) ( ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) st Y0 : ( ( ) ( ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is TopSpace-like holds
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) = the carrier of Y0 : ( ( ) ( ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) set ) & A : ( ( ) ( ) Subset of ) is anti-discrete holds
Y0 : ( ( ) ( ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is anti-discrete ;

theorem :: TEX_4:68
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) st ( for X0 being ( ( open ) ( TopSpace-like open ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) holds
( Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) misses X0 : ( ( open ) ( TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) or Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( open ) ( TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ) ) holds
Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is anti-discrete ;

theorem :: TEX_4:69
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) st ( for X0 being ( ( closed ) ( TopSpace-like closed ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) holds
( Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) misses X0 : ( ( closed ) ( TopSpace-like closed ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) or Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( closed ) ( TopSpace-like closed ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ) ) holds
Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is anti-discrete ;

theorem :: TEX_4:70
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( anti-discrete ) ( TopSpace-like anti-discrete almost_discrete ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for X0 being ( ( open ) ( TopSpace-like open ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) holds
( Y0 : ( ( anti-discrete ) ( TopSpace-like anti-discrete almost_discrete ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) misses X0 : ( ( open ) ( TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) or Y0 : ( ( anti-discrete ) ( TopSpace-like anti-discrete almost_discrete ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( open ) ( TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ) ;

theorem :: TEX_4:71
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( anti-discrete ) ( TopSpace-like anti-discrete almost_discrete ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for X0 being ( ( closed ) ( TopSpace-like closed ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) holds
( Y0 : ( ( anti-discrete ) ( TopSpace-like anti-discrete almost_discrete ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) misses X0 : ( ( closed ) ( TopSpace-like closed ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) or Y0 : ( ( anti-discrete ) ( TopSpace-like anti-discrete almost_discrete ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( closed ) ( TopSpace-like closed ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ) ;

definition
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let IT be ( ( ) ( ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) ;
attr IT is maximal_anti-discrete means :: TEX_4:def 16
( IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) is anti-discrete & ( for Y0 being ( ( ) ( ) SubSpace of Y : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) st Y0 : ( ( ) ( ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) is anti-discrete & the carrier of IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) c= the carrier of Y0 : ( ( ) ( ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) set ) holds
the carrier of IT : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) = the carrier of Y0 : ( ( ) ( ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) set ) ) );
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
cluster maximal_anti-discrete -> anti-discrete for ( ( ) ( ) SubSpace of Y : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
cluster non anti-discrete -> non maximal_anti-discrete for ( ( ) ( ) SubSpace of Y : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
end;

theorem :: TEX_4:72
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) = the carrier of Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) holds
( Y0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is maximal_anti-discrete iff A : ( ( ) ( ) Subset of ) is maximal_anti-discrete ) ;

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
cluster non empty open anti-discrete -> non empty maximal_anti-discrete for ( ( ) ( ) SubSpace of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
cluster non empty open non maximal_anti-discrete -> non empty non anti-discrete for ( ( ) ( ) SubSpace of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
cluster non empty anti-discrete non maximal_anti-discrete -> non empty non open for ( ( ) ( ) SubSpace of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
cluster non empty closed anti-discrete -> non empty maximal_anti-discrete for ( ( ) ( ) SubSpace of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
cluster non empty closed non maximal_anti-discrete -> non empty non anti-discrete for ( ( ) ( ) SubSpace of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
cluster non empty anti-discrete non maximal_anti-discrete -> non empty non closed for ( ( ) ( ) SubSpace of X : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) ;
end;

definition
let Y be ( ( ) ( ) TopStruct ) ;
let x be ( ( ) ( ) Point of ( ( ) ( ) set ) ) ;
func MaxADSspace x -> ( ( strict ) ( strict ) SubSpace of Y : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) means :: TEX_4:def 17
the carrier of it : ( ( ) ( ) Element of Y : ( ( non empty TopSpace-like almost_discrete ) ( non empty TopSpace-like almost_discrete ) TopStruct ) ) : ( ( ) ( ) set ) = MaxADSet x : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( ) Subset of ) ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let x be ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ;
cluster MaxADSspace x : ( ( ) ( ) Element of the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) ) : ( ( strict ) ( strict ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) -> non empty strict ;
end;

theorem :: TEX_4:73
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds Sspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty strict ) ( non empty trivial V46() V51(1 : ( ( ) ( non empty ) set ) ) strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is ( ( ) ( ) SubSpace of MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) ) ;

theorem :: TEX_4:74
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) is ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) iff TopStruct(# the carrier of (MaxADSspace y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b3 : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) = TopStruct(# the carrier of (MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b2 : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) ) ;

theorem :: TEX_4:75
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x, y being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
( the carrier of (MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) misses the carrier of (MaxADSspace y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) or TopStruct(# the carrier of (MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b2 : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) = TopStruct(# the carrier of (MaxADSspace y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace y : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b3 : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) ) ;

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
cluster strict TopSpace-like maximal_anti-discrete for ( ( ) ( ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) ) ;
end;

registration
let X be ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ;
let x be ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ;
cluster MaxADSspace x : ( ( ) ( ) Element of the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) ) -> strict maximal_anti-discrete ;
end;

theorem :: TEX_4:76
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty closed ) ( non empty TopSpace-like closed ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) is ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict TopSpace-like anti-discrete almost_discrete maximal_anti-discrete ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( non empty closed ) ( non empty TopSpace-like closed ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ;

theorem :: TEX_4:77
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty open ) ( non empty TopSpace-like open ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) is ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds
MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict TopSpace-like anti-discrete almost_discrete maximal_anti-discrete ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( non empty open ) ( non empty TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ;

theorem :: TEX_4:78
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) st Cl {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty closed ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) = {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial V170(b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) Element of bool the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) holds
Sspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) : ( ( non empty strict ) ( non empty trivial V46() V51(1 : ( ( ) ( non empty ) set ) ) strict TopSpace-like V160() anti-discrete almost_discrete ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is maximal_anti-discrete ;

notation
let Y be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
synonym Sspace A for Y | A;
end;

theorem :: TEX_4:79
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( non empty ) ( non empty ) Subset of ) holds A : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:80
for Y being ( ( non empty ) ( non empty ) TopStruct )
for Y0 being ( ( ) ( ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) )
for A being ( ( non empty ) ( non empty ) Subset of ) st A : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) holds
Sspace A : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is ( ( ) ( ) SubSpace of Y0 : ( ( ) ( ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) ) ;

registration
let Y be ( ( non trivial ) ( non empty non trivial ) TopStruct ) ;
cluster strict non proper for ( ( ) ( ) SubSpace of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) ) ;
end;

registration
let Y be ( ( non trivial ) ( non empty non trivial ) TopStruct ) ;
let A be ( ( non trivial ) ( non empty non trivial ) Subset of ) ;
cluster Sspace A : ( ( non trivial ) ( non empty non trivial ) Element of bool the carrier of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) : ( ( ) ( non empty non trivial ) set ) : ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict ) SubSpace of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) ) -> non trivial strict ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( non proper ) ( non empty non proper ) Subset of ) ;
cluster Sspace A : ( ( non proper ) ( non empty non proper ) Element of bool the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) -> strict non proper ;
end;

definition
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
func MaxADSspace A -> ( ( strict ) ( strict ) SubSpace of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) ) means :: TEX_4:def 18
the carrier of it : ( ( ) ( ) Element of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) ) : ( ( ) ( ) set ) = MaxADSet A : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopStruct ) : ( ( ) ( ) Subset of ) ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( non empty ) ( non empty ) Subset of ) ;
cluster MaxADSspace A : ( ( non empty ) ( non empty ) Element of bool the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( strict ) ( strict ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) -> non empty strict ;
end;

theorem :: TEX_4:81
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( non empty ) ( non empty ) Subset of ) holds A : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) ;

theorem :: TEX_4:82
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( non empty ) ( non empty ) Subset of ) holds Sspace A : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is ( ( ) ( ) SubSpace of MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) ) ;

theorem :: TEX_4:83
for Y being ( ( non empty ) ( non empty ) TopStruct )
for x being ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) holds TopStruct(# the carrier of (MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b2 : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) = TopStruct(# the carrier of (MaxADSspace {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace {x : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace {b2 : ( ( ) ( ) Point of ( ( ) ( non empty ) set ) ) } : ( ( ) ( non empty trivial ) Element of bool the carrier of b1 : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) ;

theorem :: TEX_4:84
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( non empty ) ( non empty ) Subset of ) st A : ( ( non empty ) ( non empty ) Subset of ) c= B : ( ( non empty ) ( non empty ) Subset of ) holds
MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is ( ( ) ( ) SubSpace of MaxADSspace B : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) ) ;

theorem :: TEX_4:85
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A being ( ( non empty ) ( non empty ) Subset of ) holds TopStruct(# the carrier of (MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b2 : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) = TopStruct(# the carrier of (MaxADSspace (MaxADSet A : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace (MaxADSet A : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace (MaxADSet b2 : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) ;

theorem :: TEX_4:86
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( non empty ) ( non empty ) Subset of ) st A : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) holds
MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) is ( ( ) ( ) SubSpace of MaxADSspace B : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) ) ;

theorem :: TEX_4:87
for Y being ( ( non empty ) ( non empty ) TopStruct )
for A, B being ( ( non empty ) ( non empty ) Subset of ) holds
( ( B : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) & A : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) ) iff TopStruct(# the carrier of (MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b2 : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) = TopStruct(# the carrier of (MaxADSspace B : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) , the topology of (MaxADSspace B : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( ) Element of bool (bool the carrier of (MaxADSspace b3 : ( ( non empty ) ( non empty ) Subset of ) ) : ( ( strict ) ( non empty strict ) SubSpace of b1 : ( ( non empty ) ( non empty ) TopStruct ) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) #) : ( ( strict ) ( non empty strict ) TopStruct ) ) ;

registration
let Y be ( ( non trivial ) ( non empty non trivial ) TopStruct ) ;
let A be ( ( non trivial ) ( non empty non trivial ) Subset of ) ;
cluster MaxADSspace A : ( ( non trivial ) ( non empty non trivial ) Element of bool the carrier of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) : ( ( ) ( non empty non trivial ) set ) : ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict ) SubSpace of Y : ( ( non trivial ) ( non empty non trivial ) TopStruct ) ) -> non trivial strict ;
end;

registration
let Y be ( ( non empty ) ( non empty ) TopStruct ) ;
let A be ( ( non proper ) ( non empty non proper ) Subset of ) ;
cluster MaxADSspace A : ( ( non proper ) ( non empty non proper ) Element of bool the carrier of Y : ( ( non empty ) ( non empty ) TopStruct ) : ( ( ) ( non empty ) set ) : ( ( ) ( non empty ) set ) ) : ( ( strict ) ( non empty strict ) SubSpace of Y : ( ( non empty ) ( non empty ) TopStruct ) ) -> strict non proper ;
end;

theorem :: TEX_4:88
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( open ) ( TopSpace-like open ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( non empty ) ( non empty ) Subset of ) st A : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) holds
MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( open ) ( TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ;

theorem :: TEX_4:89
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( closed ) ( TopSpace-like closed ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( non empty ) ( non empty ) Subset of ) st A : ( ( non empty ) ( non empty ) Subset of ) is ( ( ) ( ) Subset of ) holds
MaxADSspace A : ( ( non empty ) ( non empty ) Subset of ) : ( ( strict ) ( non empty strict TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) is ( ( ) ( TopSpace-like ) SubSpace of X0 : ( ( closed ) ( TopSpace-like closed ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) ) ;