proposition: Lemma fubini1 : \int[m1]_x F x = \int[m1 \x m2]_z f z.
proof: Proof. rewrite FE integralB; [|by[]|exact: integrable_Fplus|exact: integrable_Fminus]. by rewrite [in RHS]integralE ?fubini_tonelli1//; [exact: measurable_funeneg|exact: measurable_funepos]. 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