proposition: Lemma hornerMX p x : (p * 'X).[x] = p.[x] * x.
proof: Proof. by rewrite -[p * 'X]addr0 hornerMXaddC addr0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)