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Related papers: The bispectrum as a source of phase-sensitive inva…

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We apply the stationary phase method developed in (Assier, Shanin \& Korolkov, QJMAM, 76(1), 2022) to the problem of wave diffraction by a quarter-plane. The wave field is written as a double Fourier transform of an unknown spectral…

Analysis of PDEs · Mathematics 2023-10-30 Raphael C. Assier , Andrey V. Shanin , Andrey I. Korolkov

The mathematical representations of data in the Spherical Harmonic (SH) domain has recently regained increasing interest in the machine learning community. This technical report gives an in-depth introduction to the theoretical foundation…

Machine Learning · Computer Science 2023-07-10 Janis Keuper

The two matrix model is considered, with measure given by the exponential of a sum of polynomials in two different variables. It is shown how to derive a sequence of pairs of ``dual'' finite size systems of ODEs for the corresponding…

Exactly Solvable and Integrable Systems · Physics 2007-05-23 M. Bertola , B. Eynard , J. Harnad

Analyzing scalar and vector fields on the sphere, such as temperature or wind speed and direction on Earth, is a difficult task. Models should respect both the rotational symmetries of the sphere and the inherent symmetries of the vector…

Machine Learning · Computer Science 2026-04-01 Francesco Ballerin , Nello Blaser , Erlend Grong

We consider the problem of estimating a signal from noisy circularly-translated versions of itself, called multireference alignment (MRA). One natural approach to MRA could be to estimate the shifts of the observations first, and infer the…

Information Theory · Computer Science 2018-02-14 Tamir Bendory , Nicolas Boumal , Chao Ma , Zhizhen Zhao , Amit Singer

The identification of slow invariant manifolds (SIMs) is an essential part in model-order reduction for reactive systems. The mathematical definition of the SIM by Fenichel can be considered unsatisfactory, because it is only applicable to…

Differential Geometry · Mathematics 2019-05-08 Johannes Poppe , Dirk Lebiedz

In this paper, we describe a Bayesian nonparametric approach to make inference for a bivariate spherically symmetric distribution. We consider a Dirichlet invariant process prior on the set of all bivariate spherically symmetric…

Statistics Theory · Mathematics 2018-08-02 Reyhaneh Hosseini , Mahmoud Zarepour

In this paper we examine the existence of bicomplexified inverse Fourier transform as an extension of its complexified inverse version within the region of convergence of bicomplex Fourier transform. In this paper we use the idempotent…

Complex Variables · Mathematics 2015-11-05 A. Banerjee , S. K. Datta , Md. A. Hoque

Many phenomena are described by bivariate signals or bidimensional vectors in applications ranging from radar to EEG, optics and oceanography. The time-frequency analysis of bivariate signals is usually carried out by analyzing two separate…

Methodology · Statistics 2016-09-09 Julien Flamant , Nicolas Le Bihan , Pierre Chainais

This paper examines the existence and region of convergence of Fourier transform of the functions of bicomplex variables with the help of projection on its idempotent components as auxiliary complex planes. Several basic properties of this…

Complex Variables · Mathematics 2015-10-20 Abhijit Banerjee , Sanjib Kumar Datta , Md Azizul Hoque

Recent developments of Perturbation Theory (PT), specifically the Effective Field Theory of Large Scale Structure (EFTofLSS) and its equivalents, have proven powerful in analyzing galaxy clustering statistics such as the galaxy power…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-22 Joseph Tomlinson , Donghui Jeong

We demonstrate spectroscopy of incoherent light with sub-diffraction resolution. In a proof-of-principle experiment we analyze the spectrum of a pair of incoherent point-like sources whose separation is below the diffraction limit. The two…

We investigate three-point statistics in weak lensing convergence, through the integrated bispectrum. This statistic involves measuring power spectra in patches, and is thus easy to measure, and avoids the complexity of estimating the very…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-13 Gabriel Jung , Toshiya Namikawa , Michele Liguori , Dipak Munshi , Alan Heavens

The success of convolutional networks in learning problems involving planar signals such as images is due to their ability to exploit the translation symmetry of the data distribution through weight sharing. Many areas of science and…

Machine Learning · Computer Science 2019-04-23 Taco Cohen , Mario Geiger , Jonas Köhler , Max Welling

Spectrogram-based representations have grown to dominate the feature space for deep learning audio analysis systems, and are often adopted for speech analysis also. Initially, the primary motivator for spectrogram-based representations was…

Audio and Speech Processing · Electrical Eng. & Systems 2026-03-17 Ian McLoughlin , Lam Pham , Yan Song , Xiaoxiao Miao , Huy Phan , Pengfei Cai , Qing Gu , Jiang Nan , Haoyu Song , Donny Soh

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…

This work deals with an inverse source problem for the biharmonic wave equation. A two-stage numerical method is proposed to identify the unknown source from the multi-frequency phaseless data. In the first stage, we introduce some…

Numerical Analysis · Mathematics 2024-01-08 Yan Chang , Yukun Guo , Yue Zhao

Omnidirectional images and spherical representations of $3D$ shapes cannot be processed with conventional 2D convolutional neural networks (CNNs) as the unwrapping leads to large distortion. Using fast implementations of spherical and…

Computer Vision and Pattern Recognition · Computer Science 2020-12-09 Suhas Lohit , Shubhendu Trivedi

We extend the theory of diffeomorphism-invariant spin network states from the real-analytic category to the smooth category. Suppose that G is a compact connected semisimple Lie group and P -> M is a smooth principal G-bundle. A `cylinder…

q-alg · Mathematics 2008-02-03 John C. Baez , Stephen Sawin

We recapture Douglas' framework for twisted parametrized stable homotopy theory in the language of $\infty$- categories. A twisted spectrum is essentially a section of a bundle of presentable stable $\infty$-categories whose fiber is the…

Algebraic Topology · Mathematics 2025-12-24 Alice Hedenlund , Tasos Moulinos