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We derive in this article the exact norm in the Grand Lebesgue Spaces (GLS) estimates for Fourier transform acting on the functions defined in the infinite local compact Abelian (LCA) group, compact or discrete.

Functional Analysis · Mathematics 2017-10-10 E. Ostrovsky , L. Sirota

Let H be a subgroup of some locally compact group G. Assume H is approximable by discrete subgroups and G admits neighborhood bases which are "almost-invariant" under conjugation by finite subsets of H. Let $m: G \to \mathbb{C}$ be a…

Classical Analysis and ODEs · Mathematics 2014-07-10 Martijn Caspers , Javier Parcet , Mathilde Perrin , Éric Ricard

In this article, we obtain new results for Fourier restriction type problems on compact Lie groups. We first provide a sharp form of $L^p$ estimates of irreducible characters in terms of their Laplace-Beltrami eigenvalue and as a…

Analysis of PDEs · Mathematics 2023-12-25 Yunfeng Zhang

It is a well-known result of Eymard that the Fourier-Stieltjes algebra of a locally compact group $G$ can be identified with the dual of the group $\cs$ $C^{*}(G)$. A corresponding result for a locally compact groupoid $G$ has been…

Operator Algebras · Mathematics 2011-02-03 Alan L. T. Paterson

Let $G$ be a compact Lie group. In this article, we consider the initial value fractional wave equation with power-type nonlinearity on $G$. Mainly, we investigate some $L^{2}-L^{2}$ estimates of the solutions to the homogeneous fractional…

Analysis of PDEs · Mathematics 2022-07-12 Aparajita Dasgupta , Vishvesh Kumar , Shyam Swarup Mondal

In his classical paper, Laurent Schwartz proved that on the real line, in every linear translation invariant space of continuous complex valued functions, which is closed under compact convergence the exponential monomials span a dense…

Functional Analysis · Mathematics 2025-10-21 László Székelyhidi

We define an involution on the space of compact tempered unipotent representations of inner twists of a split simple $p$-adic group $G$ and investigate its behaviour with respect to restrictions to reductive quotients of maximal compact…

Representation Theory · Mathematics 2024-04-01 Anne-Marie Aubert , Dan Ciubotaru , Beth Romano

Let $G$ be a locally compact abelian topological group. For locally bounded measurable functions $\varphi: G\to\Bbb {C}$ we discuss notions of spectra for $\varphi$ relative to subalgebras of $L^{1}(G)$. In particular we study polynomials…

Functional Analysis · Mathematics 2013-06-05 B. Basit , A. J. Pryde

We investigate and review how Fourier transform is involved in the analysis of a twisted group algebra $L^1(G, \sigma)$ for $G=\widehat{\Gamma}\times \Gamma$ and $\sigma:G\times G \to \mathbb{T}$ 2- cocycle where $\Gamma$ is a locally…

Operator Algebras · Mathematics 2019-08-14 Hyun Ho Lee

We establish an operator-theoretic uncertainty principle over arbitrary compact groups, generalizing several previous results. As a consequence, we show that if f is in L^2(G), then the product of the measures of the supports of f and its…

Representation Theory · Mathematics 2016-10-18 Gorjan Alagic , Alexander Russell

Necessary and sufficient conditions are given for boundedness of Hausdorff operators on generalized Hardy spaces $H^p_E(G)$, real Hardy space $H^1_{\mathbb{R}}(G)$, $BMO(G)$, and $BMOA(G)$ for compact Abelian group $G$. Surprisingly, these…

Functional Analysis · Mathematics 2022-01-25 A. R. Mirotin

In this paper we establish the $L^p$-$L^q$ boundedness of Fourier multipliers on locally compact separable unimodular groups for the range of indices $1<p\leq 2 \leq q<\infty$. Our approach is based on the operator algebras techniques. The…

Operator Algebras · Mathematics 2017-03-14 Rauan Akylzhanov , Michael Ruzhansky

Wigner's little groups are the subgroups of the Lorentz group whose transformations leave the momentum of a given particle invariant. They thus define the internal space-time symmetries of relativistic particles. These symmetries take…

General Physics · Physics 2017-07-14 Sibel Baskal , Young S. Kim , Marilyn E. Noz

The cross-Wigner distribution $W(f,g)$ of two functions or temperate distributions $f,g$ is a fundamental tool in quantum mechanics and in signal analysis. Usually, in applications in time-frequency analysis $f$ and $g$ belong to some…

Functional Analysis · Mathematics 2018-03-23 Elena Cordero , Fabio Nicola

By the important applications of Gabor transform in time-frequency analysis and signal analysis, in this paper, we consider the Gabor quaternion Fourier transform (GQFT), and we prove of it a version Benedicks-type uncertainty principle for…

Classical Analysis and ODEs · Mathematics 2019-03-14 M. El Kassimi , S. Fahlaoui

An $L^2$ Fourier restriction argument of Bak and Seeger is abstracted to the setting of locally compact abelian groups. This is used to prove new restriction estimates for varieties lying in modules over local fields or rings of integers…

Classical Analysis and ODEs · Mathematics 2018-01-11 Jonathan Hickman , James Wright

In this paper, we investigate the $H^p(G) \rightarrow L^p(G)$, $0< p \leq 1$, boundedness of multiplier operators defined via group Fourier transform on a graded Lie group $G$, where $H^p(G)$ is the Hardy space on $G$. Our main result…

Classical Analysis and ODEs · Mathematics 2022-10-07 Qing Hong , Guorong Hu , Michael Ruzhansky

We study the boundedness of the Hilbert transform $H$ and the Hilbert maximal operator $H^*$ on weighted Lorentz spaces $\Lambda^p_u(w)$. We start by giving several necessary conditions that, in particular, lead us to the complete…

Classical Analysis and ODEs · Mathematics 2024-02-09 Elona Agora , María J. Carro , Javier Soria

We completely characterize the boundedness on $L^p$ spaces and on Wiener amalgam spaces of the short-time Fourier transform (STFT) and of a special class of pseudodifferential operators, called localization operators. Precisely, a…

Analysis of PDEs · Mathematics 2016-06-28 Elena Cordero , Fabio Nicola

We prove variants of Wiener's Tauberian theorem in the framework of quantum harmonic analysis, i.e. for convolutions between an absolutely integrable function and a trace class operator, or of two trace class operators. Our results include…

Functional Analysis · Mathematics 2020-12-18 Franz Luef , Eirik Skrettingland