proposition: Lemma hornerC c x : (c%:P).[x] = c.
proof: Proof. by rewrite /horner polyseqC; case: eqP; rewrite /= ?simp. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)