Radial Projections in $\mathbb{R}^n$ Revisited

Fuente: arXiv
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Auteurs principaux: Bright, Paige, Fu, Yuqiu, Ren, Kevin
Format: Preprint
Publié: 2024
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author Bright, Paige
Fu, Yuqiu
Ren, Kevin
author_facet Bright, Paige
Fu, Yuqiu
Ren, Kevin
contents 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 \[ \sup_{x\in X} \dim π_x(Y\setminus \{x\}) \geq \min \{\dim X + \dim Y - k, k\}. \] 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.
format Preprint
id arxiv_https___arxiv_org_abs_2406_09707
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Radial Projections in $\mathbb{R}^n$ Revisited
Bright, Paige
Fu, Yuqiu
Ren, Kevin
Classical Analysis and ODEs
Combinatorics
Metric Geometry
28A78, 28A80
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 \[ \sup_{x\in X} \dim π_x(Y\setminus \{x\}) \geq \min \{\dim X + \dim Y - k, k\}. \] 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.
title Radial Projections in $\mathbb{R}^n$ Revisited
topic Classical Analysis and ODEs
Combinatorics
Metric Geometry
28A78, 28A80
url https://arxiv.org/abs/2406.09707