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Related papers: New curved Kakeya estimates

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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

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

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

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 a bilinear Kakeya inequality in the first Heisenberg group and a sharp bilinear Kakeya estimate for Euclidean curved tubes in $\R^2$. By adapting an argument of F\"assler, Pinamonti and Wald involving Heisenberg projections, we…

Classical Analysis and ODEs · Mathematics 2026-04-06 Yannis Galanos

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

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

This paper studies the structure of Kakeya sets in $\mathbb{R}^3$. We show that for every Kakeya set $K\subset\mathbb{R}^3$, there exist well-separated scales $0<\delta<\rho\leq 1$ so that the $\delta$ neighborhood of $K$ is almost as large…

Classical Analysis and ODEs · Mathematics 2025-05-07 Hong Wang , Joshua Zahl

We establish new estimates on the Minkowski and Hausdorff dimensions of Besicovitch sets and obtain new bounds on the Kakeya maximal operator.

Classical Analysis and ODEs · Mathematics 2007-05-23 Nets Katz , Terence Tao

We study several distinct but related Fourier analytic variants of the well-known Kakeya and Furstenberg set problems in the plane. For example, given $0<s,t<1$, we call a set $K \subseteq \mathbb{R}^2$ an $(s,t)$-Kakeya set if there exists…

Classical Analysis and ODEs · Mathematics 2026-05-22 Jonathan M. Fraser , Lijian Yang

We investigate analogues for curves of the Kakeya problem for straight lines. These arise from H"ormander-type oscillatory integrals in the same way as the straight line case comes from the restriction and Bochner-Riesz problems. Using some…

Classical Analysis and ODEs · Mathematics 2007-05-23 Laura Wisewell

By combining the planebrush argument of Katz and Zahl \cite{katz21} with the decoupling-incidence method of Wang and Wu \cite{WangWu2024}, we derive new bounds for the Fourier restriction problem and the Bochner--Riesz problem, extending…

Classical Analysis and ODEs · Mathematics 2025-12-01 Tainara Borges , Tiklung Chan , Mingfeng Chen , Diankun Liu , Yakun Xi , Yufei Zhan

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

We consider Guth's approach to the Fourier restriction problem via polynomial partitioning. By writing out his induction argument as a recursive algorithm and introducing new geometric information, known as the polynomial Wolff axioms, we…

Classical Analysis and ODEs · Mathematics 2019-09-26 Jonathan Hickman , Keith M. Rogers

We show that for each odd integer $n\ge 3$, there is an open dense subset of H\"ormander phase functions in $\mathbb{R}^n$ for which the associated curved Kakeya sets have Hausdorff dimension at least $\frac{n+1}{2} + d_n$ for some positive…

Classical Analysis and ODEs · Mathematics 2025-09-16 Shaoming Guo , Diankun Liu , Yakun Xi

I show that $L^{p}-L^{q}$ estimates for the Kakeya maximal function yield lower bounds for the conformal dimension of Kakeya sets, and upper bounds for how much quasisymmetries can increase the Hausdorff dimension of line segments inside…

Classical Analysis and ODEs · Mathematics 2017-08-30 Tuomas Orponen

A Kakeya set is a compact subset of $\mathbb{R}^n$ that contains a unit line segment pointing in every direction. The Kakeya conjecture asserts that such sets must have Hausdorff and Minkowski dimension $n$. There is a special class of…

Classical Analysis and ODEs · Mathematics 2025-12-09 Hong Wang , Joshua Zahl

We propose to study the restriction conjecture using decoupling theorems and two-ends Furstenberg inequalities. Specifically, we pose a two-ends Furstenberg conjecture, which implies the restriction conjecture. As evidence, we prove this…

Classical Analysis and ODEs · Mathematics 2024-12-20 Hong Wang , Shukun Wu

We consider unions of $SL(2)$ lines in $\mathbb{R}^{3}$. These are lines of the form $$L = (a,b,0) + \mathrm{span}(c,d,1),$$ where $ad - bc = 1$. We show that if $\mathcal{L}$ is a Kakeya set of $SL(2)$ lines, then the union $\cup…

Classical Analysis and ODEs · Mathematics 2022-10-19 Katrin Fässler , Tuomas Orponen

We introduce a new concept of dimension for metric spaces, the so-called topological Hausdorff dimension. It is defined by a very natural combination of the definitions of the topological dimension and the Hausdorff dimension. The value of…

Classical Analysis and ODEs · Mathematics 2015-04-21 Richárd Balka , Zoltán Buczolich , Márton Elekes
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