proposition: Lemma is_max_approxRNE m j : E m j = [set x| F_ m x = g_ j x] `&` [set x |forall k, (k < j)%nat -> g_ k x < g_ j x].
proof: Proof. by apply/seteqP; split. Qed.
imports: mathcomp(all_ssreflect ssralg ssrnum ssrint interval) mathcomp(finmap fingroup perm rat) mathcomp(mathcomp_extra boolp classical_sets cardinality) mathcomp(functions fsbigop set_interval) HB(structures) reals ereal signed topology numfun normedtype sequences esum measure realfun lebesgue_measure lebesgue_integral