proposition: Lemma iscvgD (u v : nat -> R) : iscvg u -> iscvg v -> iscvg (u \+ v).
proof: Proof. by case=> [lu cu] [lv cv]; exists (lu + lv); apply/ncvgD. 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