proposition: Lemma pO_reduceplus : forall (Q : list (poly A0 eqA ltM)) (p q : list (Term A n)), reduceplus Q (pO A n) p -> p = pO A n.
proof: Proof. intros Q p q H'; inversion H'; auto. inversion H; auto. case (pO_reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q y); auto. Qed.