proposition: Lemma in_mon_X_Der_imp_inmon_X : forall (X V R : Ensf) (u v : Word), Regles X V R -> Derive R u v -> inmonoid (union X V) u -> inmonoid (union X V) v.
proof: Proof. intros X V1 R1 u v Regles_R1 Der_R1. elim Der_R1; prolog [ Regles_inv2 inmonoid_cons_inv inmonoid_cons_inv2 inmonoid_cons inmonoid_Append ] 10. Qed.
imports: Ensf Words more_words need fonctions Relations