proposition: Lemma cvgB f g a b : f @ F --> a -> g @ F --> b -> (f - g) @ F --> a - b.
proof: Proof. by move=> ? ?; apply: cvgD => //; apply: cvgN. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrint ssrnum finmap matrix) mathcomp(rat interval zmodp vector fieldext falgebra) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality set_interval Rstruct) ereal reals signed topology prodnormedzmodule