proposition: Lemma natrE x : (x \is a nat_num) = ((Def.trunc x)%:R == x).
proof: Proof. exact: Num.nat_num_subproof. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)