proposition: Lemma sfun_fubini_tonelli : \int[m1 \x m2]_z (f z)%:E = \int[m1 \x^ m2]_z (f z)%:E.
proof: Proof. apply: eq_measure_integral => /= A Ameasurable _. by apply: product_measure_unique => //= *; rewrite product_measure2E. 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