let X, W be set ; :: thesis: ( ( ( X in Tarski-Class W & W is epsilon-transitive ) or ( X in Tarski-Class W & X c= Tarski-Class W ) or ( card X in card (Tarski-Class W) & X c= Tarski-Class W ) ) implies Funcs X,(Tarski-Class W) c= Tarski-Class W )
assume A1:
( ( X in Tarski-Class W & W is epsilon-transitive ) or ( X in Tarski-Class W & X c= Tarski-Class W ) or ( card X in card (Tarski-Class W) & X c= Tarski-Class W ) )
; :: thesis: Funcs X,(Tarski-Class W) c= Tarski-Class W
( W is epsilon-transitive implies Tarski-Class W is epsilon-transitive )
by CLASSES1:27;
then A2:
( X c= Tarski-Class W & card X in card (Tarski-Class W) )
by A1, CLASSES1:28, ORDINAL1:def 2;
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in Funcs X,(Tarski-Class W) or x in Tarski-Class W )
assume A3:
x in Funcs X,(Tarski-Class W)
; :: thesis: x in Tarski-Class W
then consider f being Function such that
A4:
( x = f & dom f = X & rng f c= Tarski-Class W )
by FUNCT_2:def 2;
A5:
f c= Tarski-Class W
card f = card X
by A3, A4, CARD_2:7;
hence
x in Tarski-Class W
by A2, A4, A5, CLASSES1:9; :: thesis: verum