(* idem depprod *)

Inductive depprod' (A : Type) (P : A -> Type) : Type :=
    dep_i' : forall x : A, P x -> depprod' A P.(* idem depprod *)

Inductive depprod' (A : Type) (P : A -> Type) : Type :=
    dep_i' : forall x : A, P x -> depprod' A P.

Theorem Union_soundC : forall E E' : Ens, EQC E E' -> EQC (Union E) (Union E').