proposition: Lemma rootPf p x : reflect ((p.[x] == 0) = false) (~~ root p x).
proof: Proof. exact: negPf. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)