proposition: Theorem pluspf_inv2_eq : forall a b p q, ltT ltM a b -> pX b (pluspf (pX a p) q) = pluspf (pX a p) (pX b q).
proof: Proof. Proof using os. intros a b p q H'; rewrite (plusP_inv2 a b p q (pluspf (pX a p) (pX b q))); auto. Qed.
imports: Coq(Arith) Buchberger(LetP)