proposition: Lemma real_exprn_odd_le0 n x : x \is real -> odd n -> (x ^+ n <= 0) = (x <= 0).
proof: Proof. by move=> xR n_odd; rewrite !real_leNgt ?rpred0 ?rpredX // real_exprn_odd_gt0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)