proposition: Lemma nnsfun_approxE n : nnsfun_approx n = approx n :> (T -> R).
proof: Proof. rewrite funeqE => t /=; rewrite /nnsfun_approx; unlock; rewrite /=. rewrite sum_nnsfunE; congr (_ + _). by apply: eq_bigr => i _; case: Bool.bool_dec => [h|/negP]; [|rewrite ltn_ord]. 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