proposition: Lemma Gunion_isGram : forall S : Elt, isGram X V1 R1 S1 -> isGram X V2 R2 S2 -> dans S Vu -> isGram X Vu Ru S.
proof: Proof. prolog [ isGram5 isGram1 inter_X_Vu Gunion_Regles ] 7. Qed.
imports: Ensf Words more_words need fonctions Relations gram