proposition: Lemma polyXsubC_eq0 a : ('X - a%:P == 0) = false.
proof: Proof. by rewrite -nil_poly polyseqXsubC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)