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In this paper, we introduced the theory of the sieve function transformation. Using the principle of sieve function transformation, we improved sieve method, and obtained the difference range of similar sieve function values. For this, we…

General Mathematics · Mathematics 2025-06-06 Jinzhu Han

We show a pointwise estimate for the Fourier transform on the line involving the number of times the function changes monotonicity. The contrapositive of the theorem may be used to find a lower bound to the number of local maxima of a…

Classical Analysis and ODEs · Mathematics 2009-11-02 Ryan Berndt

This article proposes a new approach in the treatment of the Hilbert transform and some cases of the Fourier transform whose improper integrals are principal values. This approach may be useful for teaching these issues to undergraduate…

Mathematical Physics · Physics 2024-04-04 Jorge Pedraza Arpasi

Alesker has proved the existence of a remarkable isomorphism of the space of translation-invariant smooth valuations that has the same functorial properties as the classical Fourier transform. In this paper, we show how to directly describe…

Classical Analysis and ODEs · Mathematics 2023-09-14 Dmitry Faifman , Thomas Wannerer

In this article we study the basic theoretical properties of Mellin-type fractional integrals, known as generalizations of the Hadamard-type fractional integrals. We give a new approach and version, specifying their semigroup property,…

Functional Analysis · Mathematics 2016-11-25 Paul Leo Butzer , Carlo Bardaro , Ilaria Mantellini

The Fourier transform is approximated over a finite domain using a Riemann sum. This Riemann sum is then expressed in terms of the discrete Fourier transform, which allows the sum to be computed with a fast Fourier transform algorithm more…

Numerical Analysis · Mathematics 2015-08-07 Jeremy Axelrod

The Arithmetic Fourier Transform is a numerical formulation for computing Fourier series and Taylor series coefficients. It competes with the Fast Fourier Transform in terms of speed and efficiency, requiring only addition operations and…

Complex Variables · Mathematics 2020-12-15 Joel L. Schiff

Formul{\ae} are derived for expressing Cauchy and Hilbert transforms of a function $f$ in terms of Cauchy and Hilbert transforms of $f(x^r)$. When $r$ is an integer, this corresponds to evaluating the Cauchy transform of $f(x^r)$ at all…

Complex Variables · Mathematics 2013-11-12 Sheehan Olver

Many tight frames of interest are constructed via their Gramian matrix (which determines the frame up to unitary equivalence). Given such a Gramian, it can be determined whether or not the tight frame is projective group frame, i.e., is the…

Representation Theory · Mathematics 2018-06-19 Shayne Waldron

Recently we have reported a new method of rational approximation of the sinc function obtained by sampling and the Fourier transforms. However, this method requires a trigonometric multiplier that originates from shifting property of the…

General Mathematics · Mathematics 2022-10-18 Sanjar M. Abrarov , Rehan Siddiqui , Rajinder K. Jagpal , Brendan M. Quine

A rapid transformation is derived between spherical harmonic expansions and their analogues in a bivariate Fourier series. The change of basis is described in two steps: firstly, expansions in normalized associated Legendre functions of all…

Numerical Analysis · Mathematics 2017-11-07 Richard Mikael Slevinsky

The Fractional Fourier Transform (FrFT) has widespread applications in areas like signal analysis, Fourier optics, diffraction theory, etc. The Holomorphic Fractional Fourier Transform (HFrFT) proposed in the present paper may be used in…

Mathematical Physics · Physics 2019-05-13 William D. Kirwin , José Mourão , João P. Nunes , Thomas Thiemann

This note is a very basic introduction to wavelets. It starts with an orthogonal basis of piecewise constant functions, constructed by dilation and translation. The ``wavelet transform'' maps each $f(x)$ to its coefficients with respect to…

Numerical Analysis · Mathematics 2025-10-20 Gilbert Strang

A characterization of finitely generated shift-invariant subspaces is given when generators are g-minimal. An algorithm is given for the determination of the coefficients in the well known representation of the Fourier transform of an…

Classical Analysis and ODEs · Mathematics 2019-06-18 K. S. Kazarian

In this paper, we introduce the fractional Fourier series on the fractional torus and study some basic facts of fractional Fourier series, such as fractional convolution and fractional approximation. Meanwhile, fractional Fourier inversion…

Functional Analysis · Mathematics 2024-07-08 Zunwei Fu , Xianming Hou , Qingyan Wu

New sufficient conditions for representation of a function via the absolutely convergent Fourier integral are obtained in the paper. In the main result, Theorem 1.1, this is controlled by the behavior near infinity of both the function and…

Classical Analysis and ODEs · Mathematics 2009-06-01 E. Liflyand , R. Trigub

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

In this paper, we consider a method for fast numerical computation of the Fourier transform of a slowly decaying function with given accuracy in given ranges of the frequency. In these decades, some useful formulas for the Fourier transform…

Numerical Analysis · Mathematics 2015-07-28 Ken'ichiro Tanaka

The classical Fourier transform is, in essence, a way to take data and extract components (in the form of complex exponentials) which are invariant under cyclic shifts. We consider a case in which the components must instead be invariant…

Representation Theory · Mathematics 2014-06-26 Nathaniel Eldredge

We propose an alternative definition for a Tsallis entropy composition-inspired Fourier transform, which we call "$\tau_q$-Fourier transform". We comment about the underlying "covariance" on the set of algebraic fields that motivates its…

General Physics · Physics 2018-06-13 Nikolaos Kalogeropoulos
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