proposition: Lemma near_small_set : \forall E \near powerset_filter_from, F E.
proof: Proof. by exists F => //; split => //; exists setT; exact: filterT. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed