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A discrete complexified quaternion Fourier transform is introduced. This is a generalization of the discrete quaternion Fourier transform to the case where either or both of the signal/image and the transform kernel are complex…

Numerical Analysis · Mathematics 2008-03-19 Salem Said , Nicolas Le Bihan , Stephen J. Sangwine

This work studies the Fourier transform of the characteristic function of planar convex bodies averaged over affine transformations. We establish lower and upper bounds on the latter quantities in terms of the geometric properties of the…

Number Theory · Mathematics 2025-07-02 Thomas Beretti

It is well known that there is an integral theorem for quaternion-valued functions analogous to Cauchys Theorem for complex-valued functions, namely Fueters Theorem. The class of quaternionic functions for which this applies are generally…

Complex Variables · Mathematics 2023-05-31 R. A. W. Bradford

In this paper we study how zeros of the Fourier transform of a function $f: \mathbb{Z}_p^d \to \mathbb{C}$ are related to the structure of the function itself. In particular, we introduce a notion of bandwidth of such functions and discuss…

Classical Analysis and ODEs · Mathematics 2016-01-15 A. Iosevich , A. Liu , A. Mayeli , J. Pakianathan

We give two new global and algorithmic constructions of the reproducing kernel Hilbert space associated to a positive definite kernel. We further present ageneral positive definite kernel setting using bilinear forms, and we provide new…

Functional Analysis · Mathematics 2020-11-20 Daniel Alpay , Palle Jorgensen

The multiparticle density matrices for degenerate, ideal Fermi gas system in any dimension are calculated. The results are expressed as a determinant form, in which a correlation kernel plays a vital role. Interestingly, the correlation…

Quantum Physics · Physics 2014-05-01 Shigenori Tanaka

The Fourier transform is naturally defined for integrable functrions. Otherwise, it should be stipulated in which sense the Fourier transform is understood. We consider some class of radial and, generally saying, nonintegrable functions.…

funct-an · Mathematics 2008-02-03 Elijah Liflyand

We explore the connection between Hilbertian metrics and positive definite kernels on the real line. In particular, we look at a well-known characterization of translation invariant Hilbertian metrics on the real line by von Neumann and…

Functional Analysis · Mathematics 2013-02-19 Purushottam Kar , Harish Karnick

We study the question under which conditions the zero set of a (cross-) Wigner distribution W (f, g) or a short-time Fourier transform is empty. This is the case when both f and g are generalized Gaussians, but we will construct less…

Classical Analysis and ODEs · Mathematics 2018-11-12 Karlheinz Gröchenig , Philippe Jaming , Eugenia Malinnikova

With view to applications in stochastic analysis and geometry, we introduce a new correspondence for positive definite kernels (p.d.) $K$ and their associated reproducing kernel Hilbert spaces. With this we establish two kinds of…

Functional Analysis · Mathematics 2019-11-28 Palle Jorgensen , Feng Tian

We study fluctuations in the number of zeros of random analytic functions given by a Taylor series whose coefficients are independent complex Gaussians. When the functions are entire, we find sharp bounds for the asymptotic growth rate of…

Probability · Mathematics 2021-09-17 Avner Kiro , Alon Nishry

This work represents a systematic computational study of the distribution of the Fourier coefficients of cuspidal Hecke eigenforms of level $\Gamma_0(4)$ and half-integral weights. Based on substantial calculations, the question is raised…

Number Theory · Mathematics 2021-12-01 Ilker Inam , Zeynep Demirkol Özkaya , Elif Tercan , Gabor Wiese

This paper deals with some special integral transforms of Bargmann-Fock type in the setting of quaternionic valued slice hyperholomorphic and Cauchy-Fueter regular functions. The construction is based on the well-known Fueter mapping…

Complex Variables · Mathematics 2019-10-02 Kamal Diki , Rolf Sören Krausshar , Irene Sabadini

The purpose of this article is to extend the wavelet transform to quaternion algebra using the kernel of the two-sided quaternion Fourier transform (QFT). We study some fundamental properties of this extension such as scaling, translation,…

Classical Analysis and ODEs · Mathematics 2020-11-05 Youssef El Haoui , Said Fahlaoui

This work considers the algebras of functions in the quantum matrix ball. An explicit formula for a positive invariant integral is presented.

Quantum Algebra · Mathematics 2007-05-23 D. Shklyarov , S. Sinel'shchikov , L. Vaksman

The notion of Fourier transform is among the more important tools in analysis, which has been generalized in abstract harmonic analysis to the level of abelian locally compact groups. The aim of this paper is to further generalize the…

Operator Algebras · Mathematics 2007-08-23 Byung-Jay Kahng

The explicit construction of direct and inverse Fourier's vector transform with discontinuous coefficients is presented. The technique of applying Fourier's vector transform with discontinuous coefficients for solving problems of…

Classical Analysis and ODEs · Mathematics 2013-09-26 O. Yaremko , E. Zhuravleva

We present a general Fourier analytic technique for constructing orthonormal basis expansions of translation-invariant kernels from orthonormal bases of $\mathscr{L}_2(\mathbb{R})$. This allows us to derive explicit expansions on the real…

Classical Analysis and ODEs · Mathematics 2024-05-01 Filip Tronarp , Toni Karvonen

In this paper, we define a new transform called the Gabor quaternionic Fourier transform (GQFT), which generalizes the classical windowed Fourier transform to quaternion valued-signals, we give several important properties such as the…

Classical Analysis and ODEs · Mathematics 2019-01-07 Mohammed El Kassimi , Said Fahlaoui

We consider a kernel based harmonic analysis of "boundary," and boundary representations. Our setting is general: certain classes of positive definite kernels. Our theorems extend (and are motivated by) results and notions from classical…

Functional Analysis · Mathematics 2016-11-15 Palle Jorgensen , Feng Tian