proposition: Lemma polyseqMX p : p != 0 -> p * 'X = 0 :: p :> seq R.
proof: Proof. by move=> nz_p; rewrite -[p * _]addr0 -cons_poly_def polyseq_cons nil_poly nz_p. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)