proposition: Lemma continuousB f g x : {for x, continuous f} -> {for x, continuous g} -> {for x, continuous (f - g)}.
proof: Proof. by move=> f_cont g_cont; apply: cvgB. 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