proposition: Lemma root_polyC p x : root p^:P x%:P = root p x.
proof: Proof. by rewrite rootE horner_map polyC_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)