proposition: Lemma near_withinE D F (P : set T) : (\forall x \near within D F, P x) = {near F, D `<=` P}.
proof: Proof. by []. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed