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Related papers: Sharp extension inequalities on finite fields

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In this article, we prove that all global, nonendpoint Fourier restriction inequalities for the paraboloid in $\mathbb R^{1+d}$ have extremizers and that $L^p$-normalized extremizing sequences are precompact modulo symmetries. This result…

Classical Analysis and ODEs · Mathematics 2019-11-11 Betsy Stovall

Among the class of functions on the circle with Fourier modes up to degree 120, constant functions are the unique real-valued maximizers for the endpoint Tomas-Stein inequality.

Classical Analysis and ODEs · Mathematics 2022-03-07 James Barker , Christoph Thiele , Pavel Zorin-Kranich

In this paper we prove a sharp trilinear inequality which is motivated by a program to obtain the sharp form of the $L^2 - L^6$ Tomas-Stein adjoint restriction inequality on the circle. Our method uses intricate estimates for integrals of…

Classical Analysis and ODEs · Mathematics 2021-09-30 Emanuel Carneiro , Damiano Foschi , Diogo Oliveira e Silva , Christoph Thiele

We show that, for $n\geq 3$, $\lim_{t \to 0} e^{it\Delta}f(x) = f(x)$ holds almost everywhere for all $f \in H^s (\mathbb{R}^n)$ provided that $s>\frac{n}{2(n+1)}$. Due to a counterexample by Bourgain, up to the endpoint, this result is…

Classical Analysis and ODEs · Mathematics 2019-03-14 Xiumin Du , Ruixiang Zhang

The adjoint Fourier restriction inequality for the sphere $S^2$ states that if $f\in\lt(S^2,\sigma)$ then $\widehat{f\sigma}\in L^4(\reals^3)$. We prove that all critical points $f$ of the functional…

Classical Analysis and ODEs · Mathematics 2010-06-23 Michael Christ , Shuanglin Shao

We consider the adjoint restriction inequality associated to the hypersurface $\{(\tau, \xi) : \tau = \pm|\xi|^2, \;\xi \in \mathbb{R}^d\}$ at the Stein-Tomas exponent. Extremizers exist in all dimensions and extremizing sequences are…

Classical Analysis and ODEs · Mathematics 2023-11-14 James Tautges

We prove a sharp Fourier extension inequality on the circle for the Tomas-Stein exponent for functions whose spectrum $\{\pm \lambda_n\}$ satisfies $\lambda_{n+1}>3 \lambda_{n}$.

Classical Analysis and ODEs · Mathematics 2025-10-27 Felipe Gonçalves , João Paulo Ferreira

We study sharp $p$-variational inequalities for the Hardy-Littlewood maximal operator on complete graphs, answering in the affirmative a question by Feng Liu and Qingying Xue. We also use computational assistance to find sharp constants in…

Classical Analysis and ODEs · Mathematics 2026-03-16 Cristian González-Riquelme , Vjekoslav Kovač , José Madrid

We improve the range of exponents for the restriction problem for the 3-d paraboloid over finite fields. The key new ingredient is a variant of the Bourgain-Katz-Tao finite field incidence theorem derived from sum-product estimates. In…

Classical Analysis and ODEs · Mathematics 2016-06-01 Mark Lewko

In this paper, we will use a suitable tranform to investigate the sharp constants and optimizers for the following Caffarelli-Kohn-Nirenberg inequalities for a wide range of parameters $(r,p,q,s,\mu,\sigma)$ and $0\leq a\leq1$:…

Analysis of PDEs · Mathematics 2015-10-06 Nguyen Lam , Guozhen Lu

For $\alpha\geq 2$, we investigate a class of Fourier extension operators on fractional surfaces $(\xi,|\xi|^\alpha)$. For the corresponding $\alpha$-Strichartz inequalities, by applying the missing mass method and bilinear restriction…

Classical Analysis and ODEs · Mathematics 2024-07-02 Boning Di , Dunyan Yan

In this article, we prove some total variation inequalities for maximal functions. Our results deal with two possible generalizations of the results contained in Aldaz and P\'erez L\'azaro's work, one of whose considers a variable…

Classical Analysis and ODEs · Mathematics 2018-01-31 João Pedro Ramos

We prove new Fourier restriction estimates to the unit sphere $S^{d-1}$ on the class of $O(d-k)\times O(k)$-symmetric functions, for every $d\geq 4$ and $2\leq k\leq d-2$. As an application, we establish the existence of maximizers for the…

Functional Analysis · Mathematics 2023-11-08 Rainer Mandel , Diogo Oliveira e Silva

We study the quantitative stability associated with the adjoint Fourier restriction inequality, focusing on the paraboloid and two-dimensional sphere cases. We show that these Strichartz-stability inequalities admit minimizers attaining…

Classical Analysis and ODEs · Mathematics 2026-01-21 Boning Di , Dunyan Yan

We prove a sharp quantitative version of the $p$-Sobolev inequality for any $1<p<n$, with a control on the strongest possible distance from the class of optimal functions. Surprisingly, the sharp exponent is constant for $p<2$, while it…

Functional Analysis · Mathematics 2020-03-10 Alessio Figalli , Yi Ru-Ya Zhang

We present a restriction theorem for the Fourier transform to a 2-dimensional conical surface of finite type, obtaining a sharp result, which improves previous work by Barcelo.

Classical Analysis and ODEs · Mathematics 2019-08-14 Stefan Buschenhenke

In this article, we study the problem of obtaining Lebesgue space inequalities for the Fourier restriction operator associated to rectangular pieces of the paraboloid and perturbations thereof. We state a conjecture for the dependence of…

Classical Analysis and ODEs · Mathematics 2019-11-27 Jeremy Schwend , Betsy Stovall

In this paper we study the boundedness of extension operators associated with spheres in vector spaces over finite fields.In even dimensions, we estimate the number of incidences between spheres and points in the translated set from a…

Classical Analysis and ODEs · Mathematics 2018-11-20 Alex Iosevich , Doowon Koh

We extend the estimates for maximal Fourier restriction operators proved by M\"{u}ller, Ricci, and Wright in \cite{MR3960255} and Ramos in \cite{MR4055940} to the case of arbitrary convex curves in the plane, with constants uniform in the…

Classical Analysis and ODEs · Mathematics 2024-08-15 Marco Fraccaroli

Given a smooth curve with nonzero curvature $\Sigma\subset \mathbb{R}^2$, let $E_{\Sigma}$ denote the associated Fourier extension operator. For both general compact curves and the parabola, we characterize the pairs $(p,q)\in [1,\infty]^2$…

Classical Analysis and ODEs · Mathematics 2025-09-11 Aleksandar Bulj , Shobu Shiraki