proposition: Lemma rpred_nat_num (S : semiringClosed R) x : x \is a nat_num -> x \in S.
proof: Proof. by move=> /natrP[n ->]; apply: rpred_nat. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)