proposition: Lemma ncvgN_fin u lu : ncvg u lu%:E -> ncvg (- u) (- lu)%:E.
proof: Proof. by apply/ncvgN. Qed.
imports: mathcomp(all_ssreflect all_algebra) mathcomp.bigenough.bigenough mathcomp.classical(boolp classical_sets functions) mathcomp.classical(mathcomp_extra) xfinmap ereal reals discrete topology