proposition: Lemma powR_ge0 a x : 0 <= a `^ x.
proof: Proof. by rewrite /powR; case: ifPn => // _; exact: expR_ge0. Qed.
imports: mathcomp(all_ssreflect ssralg ssrint ssrnum matrix) mathcomp(interval rat) mathcomp(boolp classical_sets functions) mathcomp(mathcomp_extra) reals ereal signed topology normedtype landau sequences derive realfun itv convex