apply Ring_theory.mkpow_th. unfold pow. intros. rewrite Nnat.N2Nat.id.
reflexivity. Qed.

(* Specifications: *)
Lemma norm_correct :
forall (l : list R) (pe : PEZ), PEevalR l pe == PhiR l (norm pe).
Lemma PolZeq_correct : forall P P' l,
PolZeq P P' = true ->
PhiR l P == PhiR l P'.