intros Q p q H'; elim H'; auto.
intros x y H H0.
apply eqp_imp_canonical with (1 := cs) (p := x); auto.
intros x y z H'0 H'1 H'2 H'3.
apply H'2; auto.
apply canonical_reduce with (1 := cs) (3 := H'0); auto.
Qed.

Theorem order_reduceplus :
forall (Q : list (poly A0 eqA ltM)) (p q : list (Term A n)),
reduceplus Q p q ->
canonical A0 eqA ltM p -> ltP (A:=A) (n:=n) ltM q p \/ eqP A eqA n p q.