fact: Definition integral mu D f (g := f \_ D) := nnintegral mu (g ^\+) - nnintegral mu (g ^\-).
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