proposition: Lemma polyC_natr n : n%:R%:P = n%:R :> {poly R}.
proof: Proof. by rewrite rmorph_nat. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)