proposition: Lemma powRAC x y z : (x `^ y) `^ z = (x `^ z) `^ y.
proof: Proof. by rewrite -!powRrM mulrC. 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