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