proposition: Lemma Ppow_N_ok : forall l, (forall P, subst_l P@l == P@l) -> forall P n, (Ppow_N P n)@l == (pow_N_gen P1 Pmul P n)@l.
proof: Proof. destruct n;simpl. - reflexivity. - rewrite Ppow_pos_ok; trivial. now rewrite Pphi1, ring_mul_1_r. Qed.
imports: Setoid BinList BinPos BinNat BinInt Ring_polynom Ncring