:: TOPS_3 semantic presentation

begin

theorem :: TOPS_3:1
for X being ( ( ) ( ) TopStruct )
for A being ( ( ) ( ) Subset of ) holds
( ( A : ( ( ) ( ) Subset of ) = {} X : ( ( ) ( ) TopStruct ) : ( ( ) ( empty boundary ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) implies A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = [#] X : ( ( ) ( ) TopStruct ) : ( ( ) ( non proper dense ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) & ( A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = [#] X : ( ( ) ( ) TopStruct ) : ( ( ) ( non proper dense ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) implies A : ( ( ) ( ) Subset of ) = {} X : ( ( ) ( ) TopStruct ) : ( ( ) ( empty boundary ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) & ( A : ( ( ) ( ) Subset of ) = {} : ( ( ) ( ) set ) implies A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) & ( A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) implies A : ( ( ) ( ) Subset of ) = {} : ( ( ) ( ) set ) ) ) ;

theorem :: TOPS_3:2
for X being ( ( ) ( ) TopStruct )
for A being ( ( ) ( ) Subset of ) holds
( ( A : ( ( ) ( ) Subset of ) = [#] X : ( ( ) ( ) TopStruct ) : ( ( ) ( non proper dense ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) implies A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = {} X : ( ( ) ( ) TopStruct ) : ( ( ) ( empty boundary ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) & ( A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = {} X : ( ( ) ( ) TopStruct ) : ( ( ) ( empty boundary ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) implies A : ( ( ) ( ) Subset of ) = [#] X : ( ( ) ( ) TopStruct ) : ( ( ) ( non proper dense ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) & ( A : ( ( ) ( ) Subset of ) = the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) implies A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = {} : ( ( ) ( ) set ) ) & ( A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = {} : ( ( ) ( ) set ) implies A : ( ( ) ( ) Subset of ) = the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) ) ;

theorem :: TOPS_3:3
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) holds (Int A : ( ( ) ( ) Subset of ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) /\ (Cl B : ( ( ) ( ) Subset of ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) c= Cl (A : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:4
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) holds Int (A : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) c= (Cl A : ( ( ) ( ) Subset of ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) \/ (Int B : ( ( ) ( ) Subset of ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:5
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for B, A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is closed holds
Int (A : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) c= A : ( ( ) ( ) Subset of ) \/ (Int B : ( ( ) ( ) Subset of ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:6
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for B, A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is closed holds
Int (A : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = Int (A : ( ( ) ( ) Subset of ) \/ (Int B : ( ( ) ( ) Subset of ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:7
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) misses Int (Cl A : ( ( ) ( ) Subset of ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) holds
Int (Cl A : ( ( ) ( ) Subset of ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = {} : ( ( ) ( ) set ) ;

theorem :: TOPS_3:8
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) \/ (Cl (Int A : ( ( ) ( ) Subset of ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) holds
Cl (Int A : ( ( ) ( ) Subset of ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ;

begin

definition
let X be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is boundary means :: TOPS_3:def 1
Int A : ( ( ) ( ) Element of K10(K10(X : ( ( ) ( ) TopStruct ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = {} : ( ( ) ( ) set ) ;
end;

theorem :: TOPS_3:9
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) holds {} X : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( empty open closed boundary nowhere_dense ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) is boundary ;

theorem :: TOPS_3:10
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is boundary holds
A : ( ( ) ( ) Subset of ) <> the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ;

theorem :: TOPS_3:11
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for B, A being ( ( ) ( ) Subset of ) st B : ( ( ) ( ) Subset of ) is boundary & A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) holds
A : ( ( ) ( ) Subset of ) is boundary ;

theorem :: TOPS_3:12
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is boundary iff for C being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) c= C : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) is closed holds
C : ( ( ) ( ) Subset of ) = the carrier of X : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:13
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is boundary iff for G being ( ( ) ( ) Subset of ) st G : ( ( ) ( ) Subset of ) <> {} : ( ( ) ( ) set ) & G : ( ( ) ( ) Subset of ) is open holds
A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) meets G : ( ( ) ( ) Subset of ) ) ;

theorem :: TOPS_3:14
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is boundary iff for F being ( ( ) ( ) Subset of ) st F : ( ( ) ( ) Subset of ) is closed holds
Int F : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = Int (F : ( ( ) ( ) Subset of ) \/ A : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) ;

theorem :: TOPS_3:15
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is boundary holds
A : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) is boundary ;

definition
let X be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is dense means :: TOPS_3:def 2
Cl A : ( ( ) ( ) Element of K10(K10(X : ( ( ) ( ) TopStruct ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ;
end;

theorem :: TOPS_3:16
for X being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) holds [#] X : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non proper open closed dense ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) is dense ;

theorem :: TOPS_3:17
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is dense holds
A : ( ( ) ( ) Subset of ) <> {} : ( ( ) ( ) set ) ;

theorem :: TOPS_3:18
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is dense iff A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is boundary ) ;

theorem :: TOPS_3:19
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is dense iff for C being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) is closed holds
C : ( ( ) ( ) Subset of ) = the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) ;

theorem :: TOPS_3:20
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is dense iff for G being ( ( ) ( ) Subset of ) st G : ( ( ) ( ) Subset of ) is open holds
Cl G : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = Cl (G : ( ( ) ( ) Subset of ) /\ A : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) ) ;

theorem :: TOPS_3:21
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is dense holds
A : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is dense ;

definition
let X be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is nowhere_dense means :: TOPS_3:def 3
Int (Cl A : ( ( ) ( ) Element of K10(K10(X : ( ( ) ( ) TopStruct ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = {} : ( ( ) ( ) set ) ;
end;

theorem :: TOPS_3:22
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) holds {} X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( empty open closed boundary nowhere_dense ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is nowhere_dense ;

theorem :: TOPS_3:23
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is nowhere_dense holds
A : ( ( ) ( ) Subset of ) <> the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ;

theorem :: TOPS_3:24
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is nowhere_dense holds
Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is nowhere_dense ;

theorem :: TOPS_3:25
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is nowhere_dense holds
not A : ( ( ) ( ) Subset of ) is dense ;

theorem :: TOPS_3:26
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for B, A being ( ( ) ( ) Subset of ) st B : ( ( ) ( ) Subset of ) is nowhere_dense & A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) holds
A : ( ( ) ( ) Subset of ) is nowhere_dense ;

theorem :: TOPS_3:27
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is nowhere_dense iff ex C being ( ( ) ( ) Subset of ) st
( A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) is closed & C : ( ( ) ( ) Subset of ) is boundary ) ) ;

theorem :: TOPS_3:28
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is nowhere_dense iff for G being ( ( ) ( ) Subset of ) st G : ( ( ) ( ) Subset of ) <> {} : ( ( ) ( ) set ) & G : ( ( ) ( ) Subset of ) is open holds
ex H being ( ( ) ( ) Subset of ) st
( H : ( ( ) ( ) Subset of ) c= G : ( ( ) ( ) Subset of ) & H : ( ( ) ( ) Subset of ) <> {} : ( ( ) ( ) set ) & H : ( ( ) ( ) Subset of ) is open & A : ( ( ) ( ) Subset of ) misses H : ( ( ) ( ) Subset of ) ) ) ;

theorem :: TOPS_3:29
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is nowhere_dense holds
A : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is nowhere_dense ;

theorem :: TOPS_3:30
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is nowhere_dense & B : ( ( ) ( ) Subset of ) is boundary holds
A : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is boundary ;

definition
let X be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
attr A is everywhere_dense means :: TOPS_3:def 4
Cl (Int A : ( ( ) ( ) Element of K10(K10(X : ( ( ) ( ) TopStruct ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = [#] X : ( ( ) ( ) TopStruct ) : ( ( ) ( non proper dense ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;
end;

definition
let X be ( ( ) ( ) TopStruct ) ;
let A be ( ( ) ( ) Subset of ) ;
redefine attr A is everywhere_dense means :: TOPS_3:def 5
Cl (Int A : ( ( ) ( ) Element of K10(K10(X : ( ( ) ( ) TopStruct ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ;
end;

theorem :: TOPS_3:31
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) holds [#] X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty non proper open closed dense non boundary ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is everywhere_dense ;

theorem :: TOPS_3:32
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense holds
Int A : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is everywhere_dense ;

theorem :: TOPS_3:33
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense holds
A : ( ( ) ( ) Subset of ) is dense ;

theorem :: TOPS_3:34
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense holds
A : ( ( ) ( ) Subset of ) <> {} : ( ( ) ( ) set ) ;

theorem :: TOPS_3:35
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is everywhere_dense iff Int A : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is dense ) ;

theorem :: TOPS_3:36
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is open & A : ( ( ) ( ) Subset of ) is dense holds
A : ( ( ) ( ) Subset of ) is everywhere_dense ;

theorem :: TOPS_3:37
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense holds
not A : ( ( ) ( ) Subset of ) is boundary ;

theorem :: TOPS_3:38
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense & A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) holds
B : ( ( ) ( ) Subset of ) is everywhere_dense ;

theorem :: TOPS_3:39
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is everywhere_dense iff A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is nowhere_dense ) ;

theorem :: TOPS_3:40
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is nowhere_dense iff A : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is everywhere_dense ) ;

theorem :: TOPS_3:41
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is everywhere_dense iff ex C being ( ( ) ( ) Subset of ) st
( C : ( ( ) ( ) Subset of ) c= A : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) is open & C : ( ( ) ( ) Subset of ) is dense ) ) ;

theorem :: TOPS_3:42
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A being ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is everywhere_dense iff for F being ( ( ) ( ) Subset of ) st F : ( ( ) ( ) Subset of ) <> the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) & F : ( ( ) ( ) Subset of ) is closed holds
ex H being ( ( ) ( ) Subset of ) st
( F : ( ( ) ( ) Subset of ) c= H : ( ( ) ( ) Subset of ) & H : ( ( ) ( ) Subset of ) <> the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) & H : ( ( ) ( ) Subset of ) is closed & A : ( ( ) ( ) Subset of ) \/ H : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) ) ;

theorem :: TOPS_3:43
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense holds
A : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is everywhere_dense ;

theorem :: TOPS_3:44
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense & B : ( ( ) ( ) Subset of ) is everywhere_dense holds
A : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is everywhere_dense ;

theorem :: TOPS_3:45
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense & B : ( ( ) ( ) Subset of ) is dense holds
A : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is dense ;

theorem :: TOPS_3:46
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is dense & B : ( ( ) ( ) Subset of ) is nowhere_dense holds
A : ( ( ) ( ) Subset of ) \ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is dense ;

theorem :: TOPS_3:47
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense & B : ( ( ) ( ) Subset of ) is boundary holds
A : ( ( ) ( ) Subset of ) \ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is dense ;

theorem :: TOPS_3:48
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for A, B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) is everywhere_dense & B : ( ( ) ( ) Subset of ) is nowhere_dense holds
A : ( ( ) ( ) Subset of ) \ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) is everywhere_dense ;

theorem :: TOPS_3:49
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for D being ( ( ) ( ) Subset of ) st D : ( ( ) ( ) Subset of ) is everywhere_dense holds
ex C, B being ( ( ) ( ) Subset of ) st
( C : ( ( ) ( ) Subset of ) is open & C : ( ( ) ( ) Subset of ) is dense & B : ( ( ) ( ) Subset of ) is nowhere_dense & C : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = D : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) misses B : ( ( ) ( ) Subset of ) ) ;

theorem :: TOPS_3:50
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for D being ( ( ) ( ) Subset of ) st D : ( ( ) ( ) Subset of ) is everywhere_dense holds
ex C, B being ( ( ) ( ) Subset of ) st
( C : ( ( ) ( ) Subset of ) is open & C : ( ( ) ( ) Subset of ) is dense & B : ( ( ) ( ) Subset of ) is closed & B : ( ( ) ( ) Subset of ) is boundary & C : ( ( ) ( ) Subset of ) \/ (D : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = D : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) misses B : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) ;

theorem :: TOPS_3:51
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for D being ( ( ) ( ) Subset of ) st D : ( ( ) ( ) Subset of ) is nowhere_dense holds
ex C, B being ( ( ) ( ) Subset of ) st
( C : ( ( ) ( ) Subset of ) is closed & C : ( ( ) ( ) Subset of ) is boundary & B : ( ( ) ( ) Subset of ) is everywhere_dense & C : ( ( ) ( ) Subset of ) /\ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = D : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) ;

theorem :: TOPS_3:52
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for D being ( ( ) ( ) Subset of ) st D : ( ( ) ( ) Subset of ) is nowhere_dense holds
ex C, B being ( ( ) ( ) Subset of ) st
( C : ( ( ) ( ) Subset of ) is closed & C : ( ( ) ( ) Subset of ) is boundary & B : ( ( ) ( ) Subset of ) is open & B : ( ( ) ( ) Subset of ) is dense & C : ( ( ) ( ) Subset of ) /\ (D : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = D : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) misses B : ( ( ) ( ) Subset of ) & C : ( ( ) ( ) Subset of ) \/ B : ( ( ) ( ) Subset of ) : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = the carrier of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) ;

begin

theorem :: TOPS_3:53
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( ) ( TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st B : ( ( ) ( ) Subset of ) c= A : ( ( ) ( ) Subset of ) holds
Cl B : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b2 : ( ( ) ( TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) c= Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:54
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( ) ( TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for C, A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) is closed & C : ( ( ) ( ) Subset of ) c= the carrier of Y0 : ( ( ) ( TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( ) set ) & A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = Cl B : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b2 : ( ( ) ( TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:55
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( non empty closed ) ( non empty TopSpace-like closed ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
Cl A : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = Cl B : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b2 : ( ( non empty closed ) ( non empty TopSpace-like closed ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:56
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( ) ( TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) holds
Int A : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) c= Int B : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b2 : ( ( ) ( TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:57
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 C, A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) is open & C : ( ( ) ( ) Subset of ) c= 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 ) & A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
Int A : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = Int B : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b2 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:58
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for Y0 being ( ( non empty open ) ( non empty TopSpace-like open ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
Int A : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) = Int B : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b2 : ( ( non empty open ) ( non empty TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:59
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( ) ( TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) is dense holds
B : ( ( ) ( ) Subset of ) is dense ;

theorem :: TOPS_3:60
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( ) ( TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for C, A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) c= the carrier of X0 : ( ( ) ( TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( ) set ) & A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
( ( C : ( ( ) ( ) Subset of ) is dense & B : ( ( ) ( ) Subset of ) is dense ) iff A : ( ( ) ( ) Subset of ) is dense ) ;

theorem :: TOPS_3:61
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) is everywhere_dense holds
B : ( ( ) ( ) Subset of ) is everywhere_dense ;

theorem :: TOPS_3:62
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for C, A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) is open & C : ( ( ) ( ) Subset of ) c= the carrier of X0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) & A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
( ( C : ( ( ) ( ) Subset of ) is dense & B : ( ( ) ( ) Subset of ) is everywhere_dense ) iff A : ( ( ) ( ) Subset of ) is everywhere_dense ) ;

theorem :: TOPS_3:63
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 A, C being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) = the carrier of X0 : ( ( non empty open ) ( non empty TopSpace-like open ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
( ( C : ( ( ) ( ) Subset of ) is dense & B : ( ( ) ( ) Subset of ) is everywhere_dense ) iff A : ( ( ) ( ) Subset of ) is everywhere_dense ) ;

theorem :: TOPS_3:64
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for C, A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) c= the carrier of X0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) & A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
( ( C : ( ( ) ( ) Subset of ) is everywhere_dense & B : ( ( ) ( ) Subset of ) is everywhere_dense ) iff A : ( ( ) ( ) Subset of ) is everywhere_dense ) ;

theorem :: TOPS_3:65
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) & B : ( ( ) ( ) Subset of ) is boundary holds
A : ( ( ) ( ) Subset of ) is boundary ;

theorem :: TOPS_3:66
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for C, A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) is open & C : ( ( ) ( ) Subset of ) c= the carrier of X0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) & A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) is boundary holds
B : ( ( ) ( ) Subset of ) is boundary ;

theorem :: TOPS_3:67
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 A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is boundary iff B : ( ( ) ( ) Subset of ) is boundary ) ;

theorem :: TOPS_3:68
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) c= B : ( ( ) ( ) Subset of ) & B : ( ( ) ( ) Subset of ) is nowhere_dense holds
A : ( ( ) ( ) Subset of ) is nowhere_dense ;

theorem :: TOPS_3:69
for X being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for X0 being ( ( non empty ) ( non empty TopSpace-like ) SubSpace of X : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) )
for C, A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st C : ( ( ) ( ) Subset of ) is open & C : ( ( ) ( ) Subset of ) c= the carrier of X0 : ( ( non empty ) ( non empty TopSpace-like ) SubSpace of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) ) : ( ( ) ( non empty ) set ) & A : ( ( ) ( ) Subset of ) c= C : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) & A : ( ( ) ( ) Subset of ) is nowhere_dense holds
B : ( ( ) ( ) Subset of ) is nowhere_dense ;

theorem :: TOPS_3:70
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 A being ( ( ) ( ) Subset of )
for B being ( ( ) ( ) Subset of ) st A : ( ( ) ( ) Subset of ) = B : ( ( ) ( ) Subset of ) holds
( A : ( ( ) ( ) Subset of ) is nowhere_dense iff B : ( ( ) ( ) Subset of ) is nowhere_dense ) ;

begin

theorem :: TOPS_3:71
for X1, X2 being ( ( ) ( ) 1-sorted ) st the carrier of X1 : ( ( ) ( ) 1-sorted ) : ( ( ) ( ) set ) = the carrier of X2 : ( ( ) ( ) 1-sorted ) : ( ( ) ( ) set ) holds
for C1 being ( ( ) ( ) Subset of )
for C2 being ( ( ) ( ) Subset of ) holds
( C1 : ( ( ) ( ) Subset of ) = C2 : ( ( ) ( ) Subset of ) iff C1 : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b1 : ( ( ) ( ) 1-sorted ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = C2 : ( ( ) ( ) Subset of ) ` : ( ( ) ( ) Element of K10( the carrier of b2 : ( ( ) ( ) 1-sorted ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) ;

theorem :: TOPS_3:72
for X1, X2 being ( ( ) ( ) TopStruct ) st the carrier of X1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) = the carrier of X2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) & ( for C1 being ( ( ) ( ) Subset of )
for C2 being ( ( ) ( ) Subset of ) st C1 : ( ( ) ( ) Subset of ) = C2 : ( ( ) ( ) Subset of ) holds
( C1 : ( ( ) ( ) Subset of ) is open iff C2 : ( ( ) ( ) Subset of ) is open ) ) holds
TopStruct(# the carrier of X1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of X1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of K10(K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of X2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of K10(K10( the carrier of b2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict ) TopStruct ) ;

theorem :: TOPS_3:73
for X1, X2 being ( ( ) ( ) TopStruct ) st the carrier of X1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) = the carrier of X2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) & ( for C1 being ( ( ) ( ) Subset of )
for C2 being ( ( ) ( ) Subset of ) st C1 : ( ( ) ( ) Subset of ) = C2 : ( ( ) ( ) Subset of ) holds
( C1 : ( ( ) ( ) Subset of ) is closed iff C2 : ( ( ) ( ) Subset of ) is closed ) ) holds
TopStruct(# the carrier of X1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of X1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of K10(K10( the carrier of b1 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) , the topology of X2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) Element of K10(K10( the carrier of b2 : ( ( ) ( ) TopStruct ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict ) TopStruct ) ;

theorem :: TOPS_3:74
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) st the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) = the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) & ( for C1 being ( ( ) ( ) Subset of )
for C2 being ( ( ) ( ) Subset of ) st C1 : ( ( ) ( ) Subset of ) = C2 : ( ( ) ( ) Subset of ) holds
Int C1 : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = Int C2 : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) holds
TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) ;

theorem :: TOPS_3:75
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) st the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) = the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) & ( for C1 being ( ( ) ( ) Subset of )
for C2 being ( ( ) ( ) Subset of ) st C1 : ( ( ) ( ) Subset of ) = C2 : ( ( ) ( ) Subset of ) holds
Cl C1 : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = Cl C2 : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ) holds
TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) ;

theorem :: TOPS_3:76
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) = D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) & D1 : ( ( ) ( ) Subset of ) is open holds
D2 : ( ( ) ( ) Subset of ) is open ;

theorem :: TOPS_3:77
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) = D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) holds
Int D1 : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = Int D2 : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:78
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) c= D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) holds
Int D1 : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) c= Int D2 : ( ( ) ( ) Subset of ) : ( ( ) ( open ) Element of K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:79
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) = D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) & D1 : ( ( ) ( ) Subset of ) is closed holds
D2 : ( ( ) ( ) Subset of ) is closed ;

theorem :: TOPS_3:80
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) = D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) holds
Cl D1 : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) = Cl D2 : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:81
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) c= D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) holds
Cl D1 : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) c= Cl D2 : ( ( ) ( ) Subset of ) : ( ( ) ( closed ) Element of K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) ;

theorem :: TOPS_3:82
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D2 : ( ( ) ( ) Subset of ) c= D1 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) & D1 : ( ( ) ( ) Subset of ) is boundary holds
D2 : ( ( ) ( ) Subset of ) is boundary ;

theorem :: TOPS_3:83
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) c= D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) & D1 : ( ( ) ( ) Subset of ) is dense holds
D2 : ( ( ) ( ) Subset of ) is dense ;

theorem :: TOPS_3:84
for X1, X2 being ( ( TopSpace-like ) ( TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D2 : ( ( ) ( ) Subset of ) c= D1 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) , the topology of X2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( TopSpace-like ) ( TopSpace-like ) TopSpace) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( strict TopSpace-like ) TopStruct ) & D1 : ( ( ) ( ) Subset of ) is nowhere_dense holds
D2 : ( ( ) ( ) Subset of ) is nowhere_dense ;

theorem :: TOPS_3:85
for X1, X2 being ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace)
for D1 being ( ( ) ( ) Subset of )
for D2 being ( ( ) ( ) Subset of ) st D1 : ( ( ) ( ) Subset of ) c= D2 : ( ( ) ( ) Subset of ) & TopStruct(# the carrier of X1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) , the topology of X1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b1 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( non empty strict TopSpace-like ) TopStruct ) = TopStruct(# the carrier of X2 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) , the topology of X2 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) Element of K10(K10( the carrier of b2 : ( ( non empty TopSpace-like ) ( non empty TopSpace-like ) TopSpace) : ( ( ) ( non empty ) set ) ) : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) ) #) : ( ( strict ) ( non empty strict TopSpace-like ) TopStruct ) & D1 : ( ( ) ( ) Subset of ) is everywhere_dense holds
D2 : ( ( ) ( ) Subset of ) is everywhere_dense ;