proposition: Lemma Regles_union : forall X V R R' : Ensf, Regles X V R -> Regles X V R' -> Regles X V (union R R').
proof: Proof. unfold Regles in |- *. intros X V R R' R_R R_R' x dans_x_union. cut (dans x R \/ dans x R'); auto. intros [HR| HR']; auto. Qed.
imports: Ensf Words more_words need fonctions Relations