intros Q p H'; elim H'; auto.
intros a p0 H'0 H'1; red in |- *; intros H'2; inversion H'2.
Qed.

Theorem not_nil_in_polySet :
forall (Q : list (poly A0 eqA ltM)) (p : list (Term A n)),
~ inPolySet (pO A n) Q.