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Related papers: Quasisymmetric maps on Kakeya sets

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A Kakeya set in $\mathbb{R}^n$ is a compact set that contains a unit line segment $I_e$ in each direction $e \in S^{n-1}$. The Kakeya conjecture states that any Kakeya set in $\mathbb{R}^n$ has Hausdorff dimension $n$. We consider a…

Classical Analysis and ODEs · Mathematics 2025-06-26 Jonathan M. Fraser , Lijian Yang

We consider (bounded) Besicovitch sets in the Heisenberg group and prove that $L^p$ estimates for the Kakeya maximal function imply lower bounds for their Heisenberg Hausdorff dimension.

Metric Geometry · Mathematics 2017-03-13 Laura Venieri

In this dissertation we define a generalization of Kakeya sets in certain metric spaces. Kakeya sets in Euclidean spaces are sets of zero Lebesgue measure containing a segment of length one in every direction. A famous conjecture, known as…

Classical Analysis and ODEs · Mathematics 2017-03-13 Laura Venieri

We prove that the Kakeya maximal conjecture is equivalent to the $\Omega$-Kakeya maximal conjecture. This completes a recent result in [2] where Keleti and Math{\'e} proved that the Kakeya conjecture is equivalent to the $\Omega$-Kakeya…

Classical Analysis and ODEs · Mathematics 2022-04-05 Anthony Gauvan

We define the Heisenberg Kakeya maximal functions $M_{\delta}f$, $0<\delta<1$, by averaging over $\delta$-neighborhoods of horizontal unit line segments in the Heisenberg group $\mathbb{H}^1$ equipped with the Kor\'{a}nyi distance…

Classical Analysis and ODEs · Mathematics 2023-11-28 Katrin Fässler , Andrea Pinamonti , Pietro Wald

Katz and Zahl used a planebrush argument to prove that Kakeya sets in $\mathbb{R}^4$ have Hausdorff dimension at least 3.059. In the special case when the Kakeya set is plany, their argument gives a better lower bound of 10/3. We give a…

Classical Analysis and ODEs · Mathematics 2026-01-13 Izabella Łaba , Mukul Rai Choudhuri , Joshua Zahl

We adapt Guth's polynomial partitioning argument for the Fourier restriction problem to the context of the Kakeya problem. By writing out the induction argument as a recursive algorithm, additional multiscale geometric information is made…

Classical Analysis and ODEs · Mathematics 2019-08-16 Jonathan Hickman , Keith M. Rogers , Ruixiang Zhang

We prove that every Kakeya set in $\mathbb{R}^3$ formed from lines of the form $(a,b,0) + \operatorname{span}(c,d,1)$ with $ad-bc=1$ must have Hausdorff dimension $3$; Kakeya sets of this type are called $SL_2$ Kakeya sets. This result was…

Classical Analysis and ODEs · Mathematics 2023-08-17 Nets Hawk Katz , Shukun Wu , Joshua Zahl

We obtain an improved Kakeya maximal function estimate and improved Kakeya Hausdorff dimension estimate in $\mathbb{R}^4$ using a new geometric argument called the planebrush. A planebrush is a higher dimensional analogue of Wolff's…

Classical Analysis and ODEs · Mathematics 2025-10-09 Nets Hawk Katz , Joshua Zahl

The Kakeya conjecture is generally formulated as one the following statements: every compact/Borel/arbitrary subset of ${\mathbb R}^n$ that contains a (unit) line segment in every direction has Hausdorff dimension $n$; or, sometimes, that…

Metric Geometry · Mathematics 2023-07-18 Tamás Keleti , András Máthé

In this paper, we will introduce and study several types of Kakeya inequalities by the maximal functions in Hardy spaces in $\RR^n$,\,$(n\geq2)$, and we could obtain several inequalities associated with the Kakeya inequalities. We will show…

Classical Analysis and ODEs · Mathematics 2022-07-01 Zhuo Ran Hu

A Kakeya set is a subset of F^n, where F is a finite field of q elements, that contains a line in every direction. In this paper we show that the size of every Kakeya set is at least C_n * q^n, where C_n depends only on n. This improves the…

Combinatorics · Mathematics 2015-05-13 Zeev Dvir

This paper presents several new results related to the Kakeya problem. First, we establish a geometric inequality which says that collections of direction-separated tubes (thin neighborhoods of line segments that point in different…

Classical Analysis and ODEs · Mathematics 2023-08-24 Joshua Zahl

Here we show some results related with Kakeya conjecture which says that for any integer $n\geq 2$, a set containing line segments in every dimension in $\mathbb{R}^n$ has full Hausdorff dimension as well as box dimension. We proved here…

Classical Analysis and ODEs · Mathematics 2017-04-17 Han Yu

Kakeya sets are compact subsets of $\mathbb{R}^n$ that contain a unit line segment pointing in every direction. The Kakeya conjecture states that such sets must have Hausdorff dimension $n$. The property of stickiness was first discovered…

Classical Analysis and ODEs · Mathematics 2024-11-01 Mukul Rai Choudhuri

We establish new linear and trilinear bounds for collections of tubes in $\mathbb{R}^4$ that satisfy the polynomial Wolff axioms. In brief, a collection of $\delta$-tubes satisfies the Wolff axioms if not too many tubes can be contained in…

Classical Analysis and ODEs · Mathematics 2019-04-23 Larry Guth , Joshua Zahl

Let $A, B$, be finite subsets of an abelian group, and let $G \subset A \times B$ be such that $# A, # B, # \{a+b: (a,b) \in G \} \leq N$. We consider the question of estimating the quantity $# \{a-b: (a,b) \in G \}$. Recently Bourgain…

Combinatorics · Mathematics 2007-05-23 Nets Hawk Katz , Terence Tao

We obtain new bounds for the Kakeya maximal conjecture in most dimensions $n<100$, as well as improved bounds for the Kakeya set conjecture when $n=7$ or $9$. For this we consider Guth and Zahl's strengthened formulation of the maximal…

Classical Analysis and ODEs · Mathematics 2019-01-08 Jonathan Hickman , Keith M Rogers

We prove that the spacetime singular set of any suitable Leray-Hopf solution of the surface quasigeostrophic equation with fractional dissipation of order $0< \alpha < \frac{1}{2}$ has Hausdorff dimension at most $\frac{1}{2\alpha^2}\,.$…

Analysis of PDEs · Mathematics 2022-02-25 Maria Colombo , Silja Haffter

We introduce canonical antisymmetric quasiconformal maps, which minimize the quasiconformality constant among maps sending the unit circle to a given quasicircle. As an application we prove Astala's conjecture that the Hausdorff dimension…

Complex Variables · Mathematics 2009-04-09 Stanislav Smirnov
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