proposition: Lemma comm_poly0 x : comm_poly 0 x.
proof: Proof. by rewrite /comm_poly !horner0 !simp. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)