proposition: Lemma poweRB x r s : x `^?(r +? - s) -> x `^ (r - s) = x `^ r * x `^ (- s).
proof: Proof. by move=> rs; rewrite poweRD. 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