(* Lemma BDD_EGAL_complete : (x,y:BDDvar) (BDDcompare x y)=EGAL -> x=y. *)

Lemma BDDcompare_le_INFERIEUR_1 :
forall x y z : BDDvar,
BDDvar_le x y = true ->
BDDcompare y z = Datatypes.Lt -> BDDcompare x z = Datatypes.Lt.