proposition: Lemma powR_gt0 a x : 0 < a -> 0 < a `^ x.
proof: Proof. by move=> a0; rewrite /powR gt_eqF// expR_gt0. 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