proposition: Lemma horner_exp p x n : (p ^+ n).[x] = p.[x] ^+ n.
proof: Proof. by rewrite horner_exp_comm //; apply: mulrC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)