intros.
apply conv_trans with (Abs A' M).
elim H; simpl in |- *; intros; auto with pts.
apply conv_trans with (Abs y M); auto with pts.
elim H0; intros; auto with pts.
apply conv_trans with (Abs A' y); auto with pts.
Qed.

(* Specifications: *)
Lemma conv_conv_app :
forall (e : env) (u u' v v' : term),
conv e u u' -> conv e v v' -> conv e (App u v) (App u' v').