:: WELLSET1 semantic presentation

begin

theorem :: WELLSET1:1
for x being ( ( ) ( ) set )
for R being ( ( Relation-like ) ( Relation-like ) Relation) holds
( x : ( ( ) ( ) set ) in field R : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) iff ex y being ( ( ) ( ) set ) st
( [x : ( ( ) ( ) set ) ,y : ( ( ) ( ) set ) ] : ( ( ) ( ) set ) in R : ( ( Relation-like ) ( Relation-like ) Relation) or [y : ( ( ) ( ) set ) ,x : ( ( ) ( ) set ) ] : ( ( ) ( ) set ) in R : ( ( Relation-like ) ( Relation-like ) Relation) ) ) ;

theorem :: WELLSET1:2
for X, Y being ( ( ) ( ) set )
for W being ( ( Relation-like ) ( Relation-like ) Relation) st X : ( ( ) ( ) set ) <> {} : ( ( ) ( empty Relation-like non-empty empty-yielding Function-like one-to-one constant functional ) set ) & Y : ( ( ) ( ) set ) <> {} : ( ( ) ( empty Relation-like non-empty empty-yielding Function-like one-to-one constant functional ) set ) & W : ( ( Relation-like ) ( Relation-like ) Relation) = [:X : ( ( ) ( ) set ) ,Y : ( ( ) ( ) set ) :] : ( ( ) ( Relation-like ) set ) holds
field W : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) = X : ( ( ) ( ) set ) \/ Y : ( ( ) ( ) set ) : ( ( ) ( ) set ) ;

scheme :: WELLSET1:sch 1
RSeparation{ F1() -> ( ( ) ( ) set ) , P1[ ( ( Relation-like ) ( Relation-like ) Relation) ] } :
ex B being ( ( ) ( ) set ) st
for R being ( ( Relation-like ) ( Relation-like ) Relation) holds
( R : ( ( Relation-like ) ( Relation-like ) Relation) in B : ( ( ) ( ) set ) iff ( R : ( ( Relation-like ) ( Relation-like ) Relation) in F1( ( ( ) ( ) set ) ) : ( ( ) ( ) set ) & P1[R : ( ( Relation-like ) ( Relation-like ) Relation) ] ) )
proof end;

theorem :: WELLSET1:3
for x, y being ( ( ) ( ) set )
for W being ( ( Relation-like ) ( Relation-like ) Relation) st x : ( ( ) ( ) set ) in field W : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) & y : ( ( ) ( ) set ) in field W : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) & W : ( ( Relation-like ) ( Relation-like ) Relation) is well-ordering & not x : ( ( ) ( ) set ) in W : ( ( Relation-like ) ( Relation-like ) Relation) -Seg y : ( ( ) ( ) set ) : ( ( ) ( ) set ) holds
[y : ( ( ) ( ) set ) ,x : ( ( ) ( ) set ) ] : ( ( ) ( ) set ) in W : ( ( Relation-like ) ( Relation-like ) Relation) ;

theorem :: WELLSET1:4
for x, y being ( ( ) ( ) set )
for W being ( ( Relation-like ) ( Relation-like ) Relation) st x : ( ( ) ( ) set ) in field W : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) & y : ( ( ) ( ) set ) in field W : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) & W : ( ( Relation-like ) ( Relation-like ) Relation) is well-ordering & x : ( ( ) ( ) set ) in W : ( ( Relation-like ) ( Relation-like ) Relation) -Seg y : ( ( ) ( ) set ) : ( ( ) ( ) set ) holds
not [y : ( ( ) ( ) set ) ,x : ( ( ) ( ) set ) ] : ( ( ) ( ) set ) in W : ( ( Relation-like ) ( Relation-like ) Relation) ;

theorem :: WELLSET1:5
for F being ( ( Relation-like Function-like ) ( Relation-like Function-like ) Function)
for D being ( ( ) ( ) set ) st ( for X being ( ( ) ( ) set ) st X : ( ( Relation-like ) ( Relation-like ) Relation) in D : ( ( ) ( ) set ) holds
( not F : ( ( Relation-like Function-like ) ( Relation-like Function-like ) Function) . X : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) in X : ( ( Relation-like ) ( Relation-like ) Relation) & F : ( ( Relation-like Function-like ) ( Relation-like Function-like ) Function) . X : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) in union D : ( ( ) ( ) set ) : ( ( ) ( ) set ) ) ) holds
ex R being ( ( Relation-like ) ( Relation-like ) Relation) st
( field R : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) c= union D : ( ( ) ( ) set ) : ( ( ) ( ) set ) & R : ( ( Relation-like ) ( Relation-like ) Relation) is well-ordering & not field R : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) in D : ( ( ) ( ) set ) & ( for y being ( ( ) ( ) set ) st y : ( ( ) ( ) set ) in field R : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) holds
( R : ( ( Relation-like ) ( Relation-like ) Relation) -Seg y : ( ( ) ( ) set ) : ( ( ) ( ) set ) in D : ( ( ) ( ) set ) & F : ( ( Relation-like Function-like ) ( Relation-like Function-like ) Function) . (R : ( ( Relation-like ) ( Relation-like ) Relation) -Seg y : ( ( ) ( ) set ) ) : ( ( ) ( ) set ) : ( ( ) ( ) set ) = y : ( ( ) ( ) set ) ) ) ) ;

theorem :: WELLSET1:6
for N being ( ( ) ( ) set ) ex R being ( ( Relation-like ) ( Relation-like ) Relation) st
( R : ( ( Relation-like ) ( Relation-like ) Relation) is well-ordering & field R : ( ( Relation-like ) ( Relation-like ) Relation) : ( ( ) ( ) set ) = N : ( ( ) ( ) set ) ) ;