{ "id": "1304.5305", "version": "v1", "published": "2013-04-19T04:08:02.000Z", "updated": "2013-04-19T04:08:02.000Z", "title": "On radii of spheres determined by subsets of Euclidean space", "authors": [ "Bochen Liu" ], "comment": "10 pages, 1 figure", "categories": [ "math.CA" ], "abstract": "In this paper we consider the problem of how large the Hausdorff dimension of $E\\subset\\R^d$ needs to be in order to ensure that the radii set of $(d-1)$-dimensional spheres determined by $E$ has positive Lebesgue measure. We also study the question of how often can a neighborhood of a given radius repeat. We obtain two results. First, by applying a general mechanism developed in \\cite{mul} for studying Falconer-type problems, we prove that a neighborhood of a given radius cannot repeat more often than the statistical bound if $\\dH(E)>d-1+\\frac{1}{d}$; In $\\R^2$, the dimensional threshold is sharp. Second, by proving an intersection theorem, we prove for a.e $a\\in\\R^d$, the radii set of $(d-1)$-spheres with center $a$ determined by $E$ must have positive Lebesgue measure if $\\dH(E)>d-1$, which is a sharp bound for this problem.", "revisions": [ { "version": "v1", "updated": "2013-04-19T04:08:02.000Z" } ], "analyses": { "subjects": [ "28A75", "42B20" ], "keywords": [ "euclidean space", "positive lebesgue measure", "radii set", "studying falconer-type problems" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1304.5305L" } } }