{ "id": "2406.09707", "version": "v1", "published": "2024-06-14T04:24:49.000Z", "updated": "2024-06-14T04:24:49.000Z", "title": "Radial Projections in $\\mathbb{R}^n$ Revisited", "authors": [ "Paige Bright", "Yuqiu Fu", "Kevin Ren" ], "comment": "17 pages", "categories": [ "math.CA", "math.CO", "math.MG" ], "abstract": "We generalize the recent results on radial projections by Orponen, Shmerkin, Wang using two different methods. In particular, we show that given $X,Y\\subset \\mathbb{R}^n$ Borel sets and $X\\neq \\emptyset$. If $\\dim Y \\in (k,k+1]$ for some $k\\in \\{1,\\dots, n-1\\}$, then \\[ \\sup_{x\\in X} \\dim \\pi_x(Y\\setminus \\{x\\}) \\geq \\min \\{\\dim X + \\dim Y - k, k\\}. \\] Our results give a new approach to solving a conjecture of Lund-Pham-Thu in all dimensions and for all ranges of $\\dim Y$. The first of our two methods for proving the above theorem is shorter, utilizing a result of the first author and Gan. Our second method, though longer, follows the original methodology of Orponen--Shmerkin--Wang, and requires a higher dimensional incidence estimate and a dual Furstenberg-set estimate for lines. These new estimates may be of independent interest.", "revisions": [ { "version": "v1", "updated": "2024-06-14T04:24:49.000Z" } ], "analyses": { "subjects": [ "28A78", "28A80" ], "keywords": [ "radial projections", "higher dimensional incidence estimate", "dual furstenberg-set estimate", "independent interest", "first author" ], "note": { "typesetting": "TeX", "pages": 17, "language": "en", "license": "arXiv", "status": "editable" } } }