proposition: Lemma comp_polyX p : 'X \Po p = p.
proof: Proof. by rewrite /(_ \Po p) map_polyX hornerX. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)