proposition: Theorem reduce_imp_reduceplus : forall (Q : list (poly A0 eqA ltM)) (p q : list (Term A n)), reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q p q -> reduceplus Q p q.
proof: Proof. Proof using plusA cs. intros Q p q H'. apply Rstar_n with (y := q); auto. Qed.