proposition: Lemma rootC a x : root a%:P x = (a == 0).
proof: Proof. by rewrite rootE hornerC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)