On restricted projections to planes in $\mathbb{R}^3$

Fuente: arXiv
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Autori principali: Gan, Shengwen, Guo, Shaoming, Guth, Larry, Harris, Terence L. J., Maldague, Dominique, Wang, Hong
Natura: Preprint
Pubblicazione: 2022
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author Gan, Shengwen
Guo, Shaoming
Guth, Larry
Harris, Terence L. J.
Maldague, Dominique
Wang, Hong
author_facet Gan, Shengwen
Guo, Shaoming
Guth, Larry
Harris, Terence L. J.
Maldague, Dominique
Wang, Hong
contents Let $γ:[0,1]\rightarrow \mathbb{S}^{2}$ be a non-degenerate curve in $\mathbb{R}^3$, that is to say, $\det\big(γ(θ),γ'(θ),γ"(θ)\big)\neq 0$. For each $θ\in[0,1]$, let $V_θ=γ(θ)^\perp$ and let $π_θ:\mathbb{R}^3\rightarrow V_θ$ be the orthogonal projections. We prove that if $A\subset \mathbb{R}^3$ is a Borel set, then for a.e. $θ\in [0,1]$ we have $\text{dim}(π_θ(A))=\min\{2,\text{dim} A\}$. More generally, we prove an exceptional set estimate. For $A\subset\mathbb{R}^3$ and $0\le s\le 2$, define $E_s(A):=\{θ\in[0,1]: \text{dim}(π_θ(A))<s\}$. We have $\text{dim}(E_s(A))\le 1+s-\text{dim}(A)$. We also prove that if $\text{dim}(A)>2$, then for a.e. $θ\in[0,1]$ we have $\mathcal{H}^2(π_θ(A))>0$.
format Preprint
id arxiv_https___arxiv_org_abs_2207_13844
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle On restricted projections to planes in $\mathbb{R}^3$
Gan, Shengwen
Guo, Shaoming
Guth, Larry
Harris, Terence L. J.
Maldague, Dominique
Wang, Hong
Classical Analysis and ODEs
Metric Geometry
Let $γ:[0,1]\rightarrow \mathbb{S}^{2}$ be a non-degenerate curve in $\mathbb{R}^3$, that is to say, $\det\big(γ(θ),γ'(θ),γ"(θ)\big)\neq 0$. For each $θ\in[0,1]$, let $V_θ=γ(θ)^\perp$ and let $π_θ:\mathbb{R}^3\rightarrow V_θ$ be the orthogonal projections. We prove that if $A\subset \mathbb{R}^3$ is a Borel set, then for a.e. $θ\in [0,1]$ we have $\text{dim}(π_θ(A))=\min\{2,\text{dim} A\}$. More generally, we prove an exceptional set estimate. For $A\subset\mathbb{R}^3$ and $0\le s\le 2$, define $E_s(A):=\{θ\in[0,1]: \text{dim}(π_θ(A))<s\}$. We have $\text{dim}(E_s(A))\le 1+s-\text{dim}(A)$. We also prove that if $\text{dim}(A)>2$, then for a.e. $θ\in[0,1]$ we have $\mathcal{H}^2(π_θ(A))>0$.
title On restricted projections to planes in $\mathbb{R}^3$
topic Classical Analysis and ODEs
Metric Geometry
url https://arxiv.org/abs/2207.13844