auto.
Qed.

(* Specifications: *)
Lemma cart_inclus :
forall a b c d : Ensf,
inclus a b -> inclus c d -> inclus (prodcart a c) (prodcart b d).
Lemma add_inclus :
forall (x : Elt) (a b : Ensf), dans x b -> inclus a b -> inclus (add x a) b.
Lemma union_inclus :
forall a b c : Ensf, inclus a c -> inclus b c -> inclus (union a b) c.
Lemma eqwordset_sym :
forall l1 l2 : wordset, eqwordset l1 l2 -> eqwordset l2 l1.
Lemma map_Id :
forall (E : Ensf) (f : Elt -> Elt), Id E f -> map f E = E :>Ensf.
Lemma Id_words_inclus :
forall (E F : Ensf) (f : Word -> Word),
inclus F E -> Id_words E f -> Id_words F f.