proposition: Lemma hornerMz n p x : (p *~ n).[x] = p.[x] *~ n.
proof: Proof. by case: n => n; rewrite ?NegzE ?mulNzr ?(hornerN, hornerMn). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)