proposition: Lemma indic_nnfun_subproof (D : set T) : @isNonNegFun T R (\1_D).
proof: Proof. by split=> //=; rewrite /indic. 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