proposition: Lemma integrable_funeneg f : mu_int f -> mu_int f^\-.
proof: Proof. move=> /integrableP[Df foo]; apply/integrableP; split. exact: measurable_funeneg. apply: le_lt_trans foo; apply: ge0_le_integral => //. - by apply/measurableT_comp => //; exact: measurable_funeneg. - exact/measurableT_comp. - by move=> t Dt; rewrite -/((abse \o f) t) fune_abse gee0_abs// leeDr. 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