proposition: Lemma add_neq0_poweRD_def x r s : (r + s != 0)%R -> x `^?(r +? s).
proof: Proof. by rewrite poweRD_defE => /negPf->. 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