intros a p; case p; auto.
intros H' H'1; unfold olist, DescA, consA in |- *; simpl in |- *;
unfold consA, nilA in |- *.
apply d_one; auto.
intros b l H' H'0.
apply olist_cons; auto.
simple inversion H'0.
discriminate H.
injection H1; injection H0; intros H'1 H'2 H'3 H'4;
(rewrite H'2; rewrite H'4); auto.
injection H2; intros H'1 H'2; rewrite H'1; auto.
unfold pO in |- *; intros H'3 H'4; inversion H'4.
Qed.

Theorem ltP_order_comp :
forall (a b c : Term A n) (p q : list (Term A n)),
ltP (pX b p) (pX a q) -> ltT a c -> ltT b c.