fact: Definition semi_additive := forall F n, (forall k : nat, measurable (F k)) -> trivIset setT F -> measurable (\big[setU/set0]_(k < n) F k) -> mu (\big[setU/set0]_(i < n) F i) = \sum_(i < n) mu (F i).
imports: mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) reals ereal signed topology normedtype sequences esum numfun HB(structures)