proposition: Lemma integrableB f g : mu_int f -> mu_int g -> mu_int (f \- g).
proof: Proof. by move=> fi gi; exact/(integrableD fi)/integrableN. Qed.
imports: HB(structures) mathcomp(all_ssreflect ssralg ssrnum ssrint interval finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) signed reals ereal topology normedtype sequences real_interval esum measure lebesgue_measure numfun