let W, X be set ; :: thesis: ( W is Tarski & ( ( X in W & W is epsilon-transitive ) or ( X in W & X c= W ) or ( card X in card W & X c= W ) ) implies Funcs X,W c= W )
assume A1:
W is Tarski
; :: thesis: ( ( not ( X in W & W is epsilon-transitive ) & not ( X in W & X c= W ) & not ( card X in card W & X c= W ) ) or Funcs X,W c= W )
then A2:
W is subset-closed
;
assume
( ( X in W & W is epsilon-transitive ) or ( X in W & X c= W ) or ( card X in card W & X c= W ) )
; :: thesis: Funcs X,W c= W
then A3:
( X c= W & card X in card W )
by A2, Th1, ORDINAL1:def 2;
let x be set ; :: according to TARSKI:def 3 :: thesis: ( not x in Funcs X,W or x in W )
assume A4:
x in Funcs X,W
; :: thesis: x in W
then consider f being Function such that
A5:
( x = f & dom f = X & rng f c= W )
by FUNCT_2:def 2;
A6:
f c= W
card f = card X
by A4, A5, CARD_2:7;
hence
x in W
by A1, A3, A5, A6, CLASSES1:2; :: thesis: verum