unfold X1', V1', R1', S1', GGG1, GG1, G1 in |- *.
apply image_isGram.
auto.
change (Mots X1') in |- *.
rewrite egal_X_X1'.
auto.
apply inter_Xim_Vim_empty; auto.
Qed.
Hint Resolve Grammaire1'.

(* Specifications: *)
Lemma Grammaire2' : isGram X V2' R2' S2'.
rewrite <- egal_X_X2'.