proposition: Lemma poweRB_defE x r s : x `^?(r +? - s) = ((r == s)%R ==> ((x != 0) && ((x \isn't a fin_num) ==> (r == 0%R) && (s == 0%R)))).
proof: Proof. by rewrite poweRD_defE subr_eq0 oppr_eq0. 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