proposition: Lemma Id_injproducd2 : forall x : Elt, dans x X -> injproducd V2 x = x :>Elt.
proof: Proof. unfold Id, injproducd in |- *. simpl in |- *. intros x dans_x_X. apply extension_out. apply inter_dans with X; auto. Qed.
imports: Ensf Words more_words Rat need fonctions Relations gram gram2 gram3 gram4