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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

We define the notion of the Fourier transform for the rook monoid (also called the symmetric inverse semigroup) and provide two efficient divide-and-conquer algorithms (fast Fourier transforms, or FFTs) for computing it. This paper marks…

Representation Theory · Mathematics 2011-08-02 Martin Malandro , Daniel N. Rockmore

Fourier transformations of several functions of one and two variables are evaluated and then used to derive some integral and series identities. It is shown that certain double Mordell integrals can be reduced to a sum of products of…

Classical Analysis and ODEs · Mathematics 2020-01-15 Martin Nicholson

Based on the matrix expression of general nonlinear numerical analogues presented by the present author, this paper proposes a novel philosophy of nonlinear computation and analysis. The nonlinear problems are considered an ill-posed linear…

Numerical Analysis · Mathematics 2025-10-20 W. Chen

Although being powerful, the differential transform method yet suffers from a drawback which is how to compute the differential transform of nonlinear non-autonomous functions that can limit its applicability. In order to overcome this…

Classical Analysis and ODEs · Mathematics 2016-12-28 Essam. R. El-Zahar , Abdelhalim Ebaid

Fourier transform is an essential ingredient in Shor's factoring algorithm. In the standard quantum circuit model with the gate set $\{\U(2), \textrm{CNOT}\}$, the discrete Fourier transforms $F_N=(\omega^{ij})_{N\times N},i,j=0,1,..., N-1,…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 Michael H. Freedman , Zhenghan Wang

Wavelets, known to be useful in non-linear multi-scale processes and in multi-resolution analysis, are shown to have a q-deformed algebraic structure. The translation and dilation operators of the theory associate with any scaling equation…

Mathematical Physics · Physics 2009-10-31 Andrei Ludu , Martin Greiner , Jerry P. Draayer

The Fractional Fourier Transform is a ubiquitous signal processing tool in basic and applied sciences. The Fractional Fourier Transform generalizes every property and application of the Fourier Transform. Despite the practical importance of…

Signal Processing · Electrical Eng. & Systems 2020-10-21 Amir R. Nafchi , Eric Hamke , Cristina Pereyra , Ramiro Jordan

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

We propose a neural network for both forward and inverse continuous nonlinear Fourier transforms, NFT and INFT respectively. We demonstrate the network's capability to perform NFT and INFT for a random mix of NFDM-QAM signals. The network…

Signal Processing · Electrical Eng. & Systems 2024-07-17 Wen Qi Zhang , Terence H. Chan , Shahraam Afshar V.

Recasting the $N$-point one loop scalar integral from Feynman to Schwinger parameters gives an integrand with a Gaussian form. By application of a Fourier transform, it is easy to derive explicit expressions for the two, three and…

High Energy Physics - Phenomenology · Physics 2017-11-27 Kamel Benhaddou

Fourier transform is applied to annular beams of simplified flat two-level geometry: bright outer ring with a darker core. The pattern of focal beam profile (i.e. far field) is calculated and characterized with respect of its intensity…

Optics · Physics 2009-04-14 D. N. Astadjov

Consider the Fourier transform on the group $GL(2,R)$ of real $2\times 2$-matrices. We show that Fourier-images of polynomial differential operators on $GL(2,R)$ are differential-difference operators with coefficients meromorphic in…

Representation Theory · Mathematics 2019-10-29 Yury A. Neretin

Quantum Fourier Transform (QFT) plays a principal role in the development of efficient quantum algorithms. Since the number of quantum bits that can currently built is limited, while many quantum technologies are inherently three- (or more)…

Quantum Physics · Physics 2007-05-23 Zeljko Zilic , Katarzyna Radecka

We study two discretisations of the nonlinear Fourier transform of AKNS-ZS type, ${\cal F}^E$ and ${\cal F}^D$. Transformation ${\cal F}^D$ is suitable for studying the distributions of the form $u = \sum_{n = 1}^N u_n \, \delta_{x_n}$,…

Mathematical Physics · Physics 2022-08-10 Pavle Saksida

UD integrals published by N. Usyukina and A. Davydychev in 1992-1993 are integrals corresponding to ladder-type Feynman diagrams. The results are UD functions $\Phi^{(L)},$ where $L$ is the number of loops. They play an important role in…

High Energy Physics - Theory · Physics 2009-10-12 Igor Kondrashuk , Anatoly Kotikov

The nonlinear Fourier transform has the potential to overcome limits on performance and achievable data rates which arise in modern optical fiber communication systems when nonlinear interference is treated as noise. The periodic nonlinear…

Signal Processing · Electrical Eng. & Systems 2020-12-24 Jan-Willem Goossens , Hartmut Hafermann , Yves Jaouën

We provide explicit commutative sequence space representations for classical function and distribution spaces on the real half-line. This is done by evaluating at the Fourier transforms of the elements of an orthonormal wavelet basis.

Functional Analysis · Mathematics 2022-08-08 Andreas Debrouwere , Lenny Neyt , Jasson Vindas

The Number Theoretic Transform (NTT) can be regarded as a variant of the Discrete Fourier Transform. NTT has been quite a powerful mathematical tool in developing Post-Quantum Cryptography and Homomorphic Encryption. The Fourier Transform…

Cryptography and Security · Computer Science 2025-09-09 Banhirup Sengupta , Peenal Gupta , Souvik Sengupta

Fourier transformations of pseudo-Boolean functions are popular tools for analyzing functions of binary sequences. Real-world functions often have structures that manifest in a sparse Fourier transform, and previous works have shown that…

Signal Processing · Electrical Eng. & Systems 2023-01-18 Yigit Efe Erginbas , Justin Singh Kang , Amirali Aghazadeh , Kannan Ramchandran