set X = {A,(Int A),(Cl A),(Int (Cl A)),(Cl (Int A)),(Cl (Int (Cl A))),(Int (Cl (Int A)))};
{A,(Int A),(Cl A),(Int (Cl A)),(Cl (Int A)),(Cl (Int (Cl A))),(Int (Cl (Int A)))} c= bool the carrier of T
proof
let x be
object ;
TARSKI:def 3 ( not x in {A,(Int A),(Cl A),(Int (Cl A)),(Cl (Int A)),(Cl (Int (Cl A))),(Int (Cl (Int A)))} or x in bool the carrier of T )
assume
x in {A,(Int A),(Cl A),(Int (Cl A)),(Cl (Int A)),(Cl (Int (Cl A))),(Int (Cl (Int A)))}
;
x in bool the carrier of T
then
(
x = A or
x = Int A or
x = Cl A or
x = Int (Cl A) or
x = Cl (Int A) or
x = Cl (Int (Cl A)) or
x = Int (Cl (Int A)) )
by ENUMSET1:def 5;
hence
x in bool the
carrier of
T
;
verum
end;
hence
{A,(Int A),(Cl A),(Int (Cl A)),(Cl (Int A)),(Cl (Int (Cl A))),(Int (Cl (Int A)))} is Subset-Family of T
; verum