intros p; case p; simpl in |- *; auto.
intros a l H'; inversion H'.
Qed.

Theorem mults_eqp_zpO :
forall a : Term A n,
~ zeroP (A:=A) A0 eqA (n:=n) a ->
forall p : list (Term A n),
eqP A eqA n (mults a p) (pO A n) -> eqP A eqA n p (pO A n).