proposition: Lemma cons_poly_def p a : cons_poly a p = p * 'X + a%:P.
proof: Proof. apply/polyP=> i; rewrite coef_cons coefD coefMX coefC. by case: ifP; rewrite !simp. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)