Qed.
Hint Resolve Nat_IN_Omega: zfc.

(* Specifications: *)
Theorem IN_Omega_EXType :
forall E : Ens, IN E Omega -> EXType _ (fun n : nat => EQ (Nat n) E).
Theorem IN_Omega_EXType :
forall E : Ens, IN E Omega -> EXType _ (fun n : nat => EQ (Nat n) E).