proposition: Lemma measure_semi_bigcup A : (forall i : nat, measurable (A i)) -> trivIset setT A -> measurable (\bigcup_n A n) -> mu (\bigcup_n A n) = \sum_(i <oo) mu (A i).
proof: Proof. by move=> Am Atriv /measure_semi_sigma_additive/cvg_lim<-//. Qed.
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)