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Related papers: A Fourier Inversion Theorem for Normal Functions

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We consider non oscillatory functions and prove an everywhere Fourier Inversion Theorem for functions of very moderate decrease. The proofs rely on some ideas in nonstandard analysis.

Classical Analysis and ODEs · Mathematics 2023-01-19 Tristram de Piro

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

Carleson's Theorem asserts the pointwise convergence of Fourier series of square integrable functions. We give a complete proof, following joint work of the author and C. Thiele. Over 20 exercises are also detailed. We also discuss the…

Classical Analysis and ODEs · Mathematics 2007-05-23 Michael Lacey

Usually such area of mathematics as differential equations acts as a consumer of results given by functional analysis. This article will give an example of the reverse interaction of these two fields of knowledge. Namely, the derivation and…

Classical Analysis and ODEs · Mathematics 2026-05-14 Alexey Gorshkov

In this paper, we study the inversion formula for recovering a function from its windowed Fourier transform. We give a rigorous proof for an inversion formula which is known in engineering. We show that the integral involved in the formula…

Functional Analysis · Mathematics 2011-09-21 Wenchang Sun

In this work we define operator-valued Fourier transforms for suitable integrable elements with respect to the Plancherel weight of a (not necessarily Abelian) locally compact group. Our main result is a generalized version of the Fourier…

Functional Analysis · Mathematics 2009-03-26 Alcides Buss

We give a simple proof of the Fourier Inversion Theorem, using the methods of nonstandard analysis.

Logic · Mathematics 2013-11-08 Tristram de Piro

Using the integral representations of the solutions of Schr\"odinger equation, which are the essential ingredients of the Gel'fand-Levitan and Marchenko integral equations of inverse scattering theory, we obtain a general theorem on the…

Mathematical Physics · Physics 2007-06-28 Khosrow Chadan

Fourier transforms are ubiquitous mathematical tools in basic and applied sciences. We here report classical and quantum optical realizations of the discrete fractional Fourier transform, a generalization of the Fourier transform. In the…

We extend the functional analytic approach to Colombeau-type spaces of nonlinear generalized functions in order to study algebras of tempered generalized functions. We obtain a definition of Fourier transform of nonlinear generalized…

Functional Analysis · Mathematics 2016-04-12 Eduard A. Nigsch

Given a charge and current distribution with compact support, the associated potentials and fields are generally not integrable in the classical sense. However, it is convenient to be able to define their Fourier transform in order to…

Mathematical Physics · Physics 2024-03-15 Tristram de Piro

In this contribution we generalize the classical Fourier Mellin transform [S. Dorrode and F. Ghorbel, Robust and efficient Fourier-Mellin transform approximations for gray-level image reconstruction and complete invariant description,…

Rings and Algebras · Mathematics 2013-06-10 Eckhard Hitzer

We propose a new integral based on Taylor measures, study its properties extensively, and we illustrate that it includes many concepts from mathematics as special cases. In particular, the new integral emerges as a generalization of the…

General Mathematics · Mathematics 2026-05-11 Athanasios Christou Micheas

The quaternion Fourier transform (QFT), a generalization of the classical 2D Fourier transform, plays an increasingly active role in particular signal and colour image processing. There tends to be an inordinate degree of interest placed on…

Classical Analysis and ODEs · Mathematics 2019-03-04 Dong Cheng , Kit Ian Kou

We systematically find conditions which yield locally uniform convergence in the Fourier inversion formula in one and higher dimensions. We apply the gained knowledge to the complex inversion formula of the Laplace transform to extend known…

Functional Analysis · Mathematics 2025-04-01 Joannis Alexopoulos

We propose a novel definition of Fourier transform, with the property that the transform of a real function is again a real function (without doubling the number of real components). We prove the inversion theorem for the novel definition,…

General Mathematics · Mathematics 2025-02-26 Fulvio Sbisà

The celebrated Carleson-Hunt theorem gives pointwise almost everywhere convergence for the Fourier series of a function in $L^p(\mathbb T)$. R. Oberlin, A. Seeger, T. Tao, C. Thiele and J. Wright (OSTTW) strengthened this theorem by proving…

Classical Analysis and ODEs · Mathematics 2025-08-26 Himali Dabhi

This article establishes a real-variable argument for Zygmund's theorem on almost everywhere convergence of strong arithmetic means of partial sums of Fourier series on $\mathbb{T}$, up to passing to a subsequence. Our approach extends to,…

Classical Analysis and ODEs · Mathematics 2013-04-15 Bobby Wilson

A simple proof is provided to show that any bounded normal operator on a real Hilbert space is orthogonally equivalent to its transpose(adjoint). A structure theorem for invertible skew-symmetric operators, which is analogous to the finite…

Spectral Theory · Mathematics 2020-04-21 B V Rajarama Bhat , Tiju Cherian John

Let $f$ be a function on the real line. The Fourier transform inversion theorem is proved under the assumption that $f$ is absolutely continuous such that $f$ and $f'$ are Lebesgue integrable. A function $g$ is defined by…

Classical Analysis and ODEs · Mathematics 2018-08-14 Erik Talvila
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