intros p a; unfold tmults in |- *; case (zeroP_dec A A0 eqA eqA_dec n a);
auto.
intros H' H'0; elim H'; auto.
Qed.

(* Specifications: *)
Theorem mults_eqp_pO_pO :
forall p a, eqP A eqA n p (pO A n) -> eqP A eqA n (mults a p) (pO A n).