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Related papers: Fourier series in weighted Lorentz spaces

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In this paper, we introduce a new class of function spaces, which unify and generalize Lorentz-Karamata spaces, variable Lorentz spaces and other several classical function spaces. Based on the new spaces, we develop the theory of variable…

Functional Analysis · Mathematics 2024-02-27 Zhiwei Hao , Xinru Ding , Libo Li , Ferenc Weisz

We define and establish the conditions for `equivalent neural networks' - neural networks with different weights, biases, and threshold functions that result in the same associated function. We prove that given a neural network…

Machine Learning · Computer Science 2021-09-09 Dinesh Valluri , Rory Campbell

It is a well known general principle that the Fourier transform of a random measure is small, except at the zero frequency, in various senses for appropriate notions of randomness. In this note we develop analogues of this principle for two…

Classical Analysis and ODEs · Mathematics 2011-08-30 Michael Christ

The quantum Fourier transform (QFT) is a fundamental primitive in quantum computation and quantum information. In this work, we generalize the QFT for finite groups to a QFT for finite-dimensional semisimple algebras, and give efficient…

Quantum Physics · Physics 2026-05-08 Ben Foxman , Barak Nehoran , Yongshan Ding

The paper deals with a fractional derivative introduced by means of the Fourier transform. The explicit form of the kernel of general derivative operator acting on the functions analytic on a curve in complex plane is deduced and the…

funct-an · Mathematics 2009-10-28 P. Zavada

In this paper, we develop boundedness estimates for Fourier integral operators on Fourier Lebesgue spaces when the associated canonical relation is parametrised by a complex phase function. Our result constitutes the complex analogue of…

Analysis of PDEs · Mathematics 2026-02-17 Duván Cardona , William Obeng-Denteh , Frederick Opoku

In a path-integral approach to quantum cosmology, the Lorenz gauge-averaging term is studied for Euclidean Maxwell theory on a portion of flat four-space bounded by two concentric three-spheres, but with arbitrary values of the gauge…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giampiero Esposito , Giuseppe Pollifrone

We establish a characterization of complex linear canonical transformations that are positive with respect to a pair of strictly plurisubharmonic quadratic weights. As an application, we show that the boundedness of a class of Toeplitz…

Functional Analysis · Mathematics 2019-07-31 Lewis Coburn , Michael Hitrik , Johannes Sjoestrand

This work is dedicated to the development of the theory of Fourier hyperfunctions in one variable with values in a complex non-necessarily metrisable locally convex Hausdorff space $E$. Moreover, necessary and sufficient conditions are…

Functional Analysis · Mathematics 2026-04-20 Karsten Kruse

Integration by parts plays a crucial role in mathematical analysis, e.g., during the proof of necessary optimality conditions in the calculus of variations and optimal control. Motivated by this fact, we construct a new, right-weighted…

Optimization and Control · Mathematics 2022-04-19 Houssine Zine , El Mehdi Lotfi , Delfim F. M. Torres , Noura Yousfi

Let $0<\alpha<n$ and $I_\alpha$ be the fractional integral operator. In this paper, we shall use a unified approach to show some boundedness properties of commutators $[b,I_\alpha]$ on the weighted Morrey spaces $L^{p,\kappa}(w)$ under…

Classical Analysis and ODEs · Mathematics 2013-01-23 Hua Wang

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

The Wigner function, which provides a phase-space description of quantum systems, has various applications in quantum mechanics, quantum kinetic theory, quantum optics, radiation transport and others. The concept of Wigner function has been…

High Energy Physics - Theory · Physics 2013-04-05 Stanislaw Mrowczynski

The final goal of the present work is to extend the Fourier transform on the Heisenberg group $\H^d,$ to tempered distributions. As in the Euclidean setting, the strategy is to first show that the Fourier transform is an isomorphism on the…

Functional Analysis · Mathematics 2017-05-08 Hajer Bahouri , Jean-Yves Chemin , Raphael Danchin

A formula which expresses logarithmic energy of Borel measures on R^n in terms of the Fourier transforms of the measures is established and some applications are given. In addition, using similar techniques a (known) formula for Riesz…

Classical Analysis and ODEs · Mathematics 2022-11-09 Leonhard Frerick , Jürgen Müller , Tobias Thomaser

We prove that the set of all integrable functions whose sequences of negative (resp. nonnegative) Fourier coefficients belong to $\ell^1\cap\ell^\Phi_{\phi,w}$ (resp. to $\ell^1\cap\ell^\Psi_{\psi,\varrho}$), where $\ell^\Phi_{\phi,w}$ and…

Functional Analysis · Mathematics 2007-05-23 Alexei Yu. Karlovich

We provide complete characterizations, on Banach spaces with cotype 2, of those linear operators which happen to be weakly mixing or strongly mixing transformations with respect to some nondegenerate Gaussian measure. These…

Functional Analysis · Mathematics 2011-12-07 Frédéric Bayart , Etienne Matheron

A proof is given for the Fourier transform for functions in a quantum mechanical Hilbert space on a non-compact manifold in general relativity. In the (configuration space) Newton-Wigner representation we discuss the spectral decomposition…

General Physics · Physics 2020-04-23 L. P. Horwitz

Building on recent progress in constructing derivations on Fourier algebras, we provide the first examples of locally compact groups whose Fourier algebras support non-zero, alternating 2-cocycles; this is the first step in a larger…

Functional Analysis · Mathematics 2021-04-26 Yemon Choi

We study weighted composition operators acting between Fock spaces. The following results are obtained: (1) Criteria for the boundedness and compactness; (2) Characterizations of compact differences and essential norm; (3) Complete…

Complex Variables · Mathematics 2017-04-13 Pham Trong Tien , Le Hai Khoi