{ "id": "1704.07210", "version": "v1", "published": "2017-04-24T13:30:06.000Z", "updated": "2017-04-24T13:30:06.000Z", "title": "An improved bound on the Hausdorff dimension of Besicovitch sets in $\\mathbb{R}^3$", "authors": [ "Nets Hawk Katz", "Joshua Zahl" ], "comment": "57 pages, 0 figures", "categories": [ "math.CA" ], "abstract": "We prove that any Besicovitch set in $\\mathbb{R}^3$ must have Hausdorff dimension at least $5/2+\\epsilon_0$ for some small constant $\\epsilon_0>0$. This follows from a more general result about the volume of unions of tubes that satisfy the Wolff axioms. Our proof grapples with a new \"almost counter example\" to the Kakeya conjecture, which we call the $SL_2$ example; this object resembles a Besicovitch set that has Minkowski dimension 3 but Hausdorff dimension $5/2$. We believe this example may be an interesting object for future study.", "revisions": [ { "version": "v1", "updated": "2017-04-24T13:30:06.000Z" } ], "analyses": { "keywords": [ "hausdorff dimension", "besicovitch set", "small constant", "object resembles", "general result" ], "note": { "typesetting": "TeX", "pages": 57, "language": "en", "license": "arXiv", "status": "editable" } } }