apply map_Id.
red in |- *.
auto.
Qed.

(* Specifications: *)
Lemma egal_X_X2' : X2' = X :>Ensf.
unfold X2' in |- *. simpl in |- *.
Lemma Grammaire1' : isGram X V1' R1' S1'.
rewrite <- egal_X_X1'.