proposition: Lemma realX n : {in real, forall x, x ^+ n \is real}.
proof: Proof. exact: rpredX. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)