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Related papers: Quasisymmetric maps on Kakeya sets

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We determine the submaximal dimensions of the spaces of almost Einstein scales and normal conformal Killing fields for connected conformal manifolds. The results depend on the signature and dimension $n$ of the conformally nonflat conformal…

Differential Geometry · Mathematics 2024-01-09 Jan Gregorovič , Josef Šilhan

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…

Classical Analysis and ODEs · Mathematics 2023-08-24 Nets Hawk Katz , Joshua Zahl

We provide quantitative estimates for the supremum of the Hausdorff dimension of sets in the real line which avoid $\varepsilon$-approximations of arithmetic progressions. Some of these estimates are in terms of Szemer\'{e}di bounds. In…

Classical Analysis and ODEs · Mathematics 2021-03-26 Jonathan M. Fraser , Pablo Shmerkin , Alexia Yavicoli

We prove that a subset of $\mathbb{F}_q^n$ that contains a hyperplane in any direction has size at least $q^{n}-O(q^2)$.

Combinatorics · Mathematics 2017-05-30 Beat Zurbuchen

Given a Cantor-type subset $\Omega$ of a smooth curve in $\mathbb R^{d+1}$, we construct examples of sets that contain unit line segments with directions from $\Omega$ and exhibit analytical features similar to those of classical Kakeya…

Classical Analysis and ODEs · Mathematics 2014-04-25 Edward Kroc , Malabika Pramanik

For Cantor circle Julia sets of hyperbolic rational maps, we prove that they are quasisymmetrically equivalent to standard Cantor circles (i.e., connected components are round circles). This gives a quasisymmetric uniformization of all…

Dynamical Systems · Mathematics 2021-01-26 Weiyuan Qiu , Fei Yang

This paper considers the problem of establishing $L^p$-improving inequalities for Radon-like operators in intermediate dimensions (i.e., for averages overs submanifolds which are neither curves nor hypersurfaces). Due to limitations in…

Classical Analysis and ODEs · Mathematics 2020-08-06 Philip T. Gressman

Let $L$ be a set of lines of an affine space over a field and let $S$ be a set of points with the property that every line of $L$ is incident with at least $N$ points of $S$. Let $D$ be the set of directions of the lines of $L$ considered…

Combinatorics · Mathematics 2016-05-04 Simeon Ball , Aart Blokhuis , Diego Domenzain

The arithmetic Kakeya conjecture, formulated by Katz and Tao in 2002, is a statement about addition of finite sets. It is known to imply a form of the Kakeya conjecture, namely that the upper Minkowski dimension of a Besicovitch set in…

Number Theory · Mathematics 2017-12-07 Ben Green , Imre Ruzsa

For a finite vector space $V$ and a non-negative integer $r\le\dim V$ we estimate the smallest possible size of a subset of $V$, containing a translate of every $r$-dimensional subspace. In particular, we show that if $K\subset V$ is the…

Number Theory · Mathematics 2010-03-22 Swastik Kopparty , Vsevolod F. Lev , Shubhangi Saraf , Madhu Sudan

A Kakeya set in $\mathbb{F}_q^n$ is a set containing a line in every direction. We show that every Kakeya set in $\mathbb{F}_q^n$ has density at least $1/2^{n-1}$, matching the construction by Dvir, Kopparty, Saraf and Sudan.

Combinatorics · Mathematics 2021-12-14 Boris Bukh , Ting-Wei Chao

The dimension of Kakeya sets can be bounded using sum-difference exponents $\SD(R;s)$ for various sets of rational slopes $R$ and output slope $s$; the arithmetic Kakeya conjecture, which implies the Kakeya conjecture in all dimensions,…

Combinatorics · Mathematics 2025-11-20 Terence Tao

Given an analytic function $f=u+iv$ in the unit disk $\mathbb{D}$, Zygmund's theorem gives the minimal growth restriction on $u$ which ensures that $v$ is in the Hardy space $h^1$. This need not be true if $f$ is a complex-valued harmonic…

Complex Variables · Mathematics 2025-01-06 Suman Das , Jie Huang , Antti Rasila

A Besicovitch set is a subset of $\R^d$ that contains a unit line segment in every direction and the famous Kakeya conjecture states that Besicovitch sets should have full dimension. We provide a number of results in support of this…

Classical Analysis and ODEs · Mathematics 2018-04-26 Jonathan M. Fraser , Eric J. Olson , James C. Robinson

We establish the following uniformization result for metric spaces $X$ of finite Hausdorff 2-measure. If $X$ is homeomorphic to a smooth 2-manifold $M$ with non-empty boundary, then we show that $X$ admits a quasiconformal almost…

Metric Geometry · Mathematics 2022-08-25 Damaris Meier

Through the use of a nonstandard version of Frostman's lemma, the notion of Hausdorff dimension is formulated in nonstandard euclidean space of arbitrary dimension. This allows for a nonstandard proof of the Kakeya conjecture in two…

Classical Analysis and ODEs · Mathematics 2013-08-29 Paul Potgieter

If the non-commutative L p space of SLn(Z) has the completely bounded approximation property for some non-trivial value of p, then some form of the Kakeya conjecture holds in dimension d, for all d $\le$ n+1 2 . The proof relies on a…

Classical Analysis and ODEs · Mathematics 2026-02-17 Mikael de la Salle

We construct a quasiconformal mapping of $n$-dimensional Euclidean space, $n \geq 2$, that simultaneously distorts the Hausdorff dimension of a nearly maximal collection of parallel lines by a given amount. This answers a question of…

Metric Geometry · Mathematics 2016-01-28 Zoltán M. Balogh , Jeremy T. Tyson , Kevin Wildrick

The connections between quasi-Assouad dimension and tangents are studied. We apply these results to the calculation of the quasi-Assouad dimension for a class of planar self-affine sets. We also show that sets with decreasing gaps have…

Classical Analysis and ODEs · Mathematics 2019-06-27 Ignacio García , Kathryn Hare

In this article, we examine stretching and rotation of planar quasiconformal mappings on a line. We show that for almost every point on the line, the set of complex stretching exponents (describing stretching and rotation jointly) is…

Complex Variables · Mathematics 2021-10-28 Olli Hirviniemi , István Prause , Eero Saksman