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We study an inverse boundary value problem for the nonlinear wave equation in $2 + 1$ dimensions. The objective is to recover an unknown potential $q(x, t)$ from the associated Dirichlet-to-Neumann map using real-valued waves. We propose a…

Numerical Analysis · Mathematics 2025-11-18 Markus Harju , Suvi Anttila , Teemu Tyni

We study higher-rank Radon transforms that take functions on $j$-dimensional totally geodesic submanifolds in the $n$-dimensional real constant curvature space to functions on similar submanifolds of dimension $k >j$. The corresponding dual…

Functional Analysis · Mathematics 2021-12-17 Boris Rubin

We study a generalized boundary rigidity problem, which investigates whether the areas of embedded minimal surfaces can uniquely determine a Riemannian manifold with boundary. We prove that for a conformal perturbation of an analytic metric…

Analysis of PDEs · Mathematics 2025-10-28 Leonard Busch , Tony Liimatainen , Mikko Salo , Leo Tzou

There has been growing recent interest in probabilistic interpretations of kernel-based methods as well as learning in Banach spaces. The absence of a useful Lebesgue measure on an infinite-dimensional reproducing kernel Hilbert space is a…

Machine Learning · Statistics 2014-03-14 Irina Holmes , Ambar Sengupta

Real physical systems are only understood, experimentally or theoretically, to a finite resolution so in their analysis there is generally an ignorance of possible short-range phenomena. It is also well-known that the boundary conditions of…

High Energy Physics - Theory · Physics 2016-06-17 David M. Jacobs

We consider weighted Radon transforms $R_W$ along hyperplanes in $R^3$ with strictly positive weights $W$. We construct an example of such a transform with non-trivial kernel $\mathrm{Ker}R_W$ in the space of infinitely smooth compactly…

Mathematical Physics · Physics 2018-06-27 Fedor Goncharov , Roman Novikov

We obtain a system of exact solutions of the Dirac equation for an electron moving in a constant homogeneous external magnetic field with account of its vacuum magnetic moment and assumed Lorentz invariance violation in the minimal CPT-odd…

High Energy Physics - Theory · Physics 2008-11-26 I. E. Frolov , V. Ch. Zhukovsky

This paper establishes $L^p$-improving estimates for a variety of Radon-like transforms which integrate functions over submanifolds of intermediate dimension. In each case, the results rely on a unique notion of curvature which relates to,…

Classical Analysis and ODEs · Mathematics 2016-09-13 Philip T. Gressman

The Born-Infeld form of the hydrogen atom has a spectrum that can be used to determine the physical viability of the theory, and place an experimentally relevant bound on the single parameter found in it. We compute this spectrum using the…

Quantum Physics · Physics 2015-05-27 J. Franklin , T. Garon

We describe the general setting for the optical Aharonov-Bohm effect based on the inverse problem of the identification of the coefficients of the governing hyperbolic equation by the boundary measurements. We interpret the inverse problem…

Mathematical Physics · Physics 2015-07-06 Gregory Eskin

Off-the-grid regularisation has been extensively employed over the last decade in the context of ill-posed inverse problems formulated in the continuous setting of the space of Radon measures $\mathcal{M}(\mathcal{X})$. These approaches…

Numerical Analysis · Mathematics 2025-04-15 Marta Lazzaretti , Claudio Estatico , Alejandro Melero , Luca Calatroni

PAT is the best-known example of a hybrid imaging method. In this article, we define a Radon-type transform arising in a version of PAT that uses integrating circle detectors and describe how the Radon transform integrating over all circles…

Functional Analysis · Mathematics 2014-12-09 Sunghwan Moon

We consider the weighted Radon transforms $R_W$ along hyperplanes in $R^d, \, d \geq 3$, with strictly positive weights $W = W (x, \theta), \, x \in R^d, \, \theta \in S^{d-1}$. We construct an example of such a transform with non-trivial…

Functional Analysis · Mathematics 2018-04-18 F Goncharov , R Novikov

We study a generalized spherical means operator, viz. generalized spherical mean Radon transform, acting on radial functions. As the main results, we find conditions for the associated maximal operator and its local variant to be bounded on…

Classical Analysis and ODEs · Mathematics 2020-10-22 Óscar Ciaurri , Adam Nowak , Luz Roncal

Spectral dimensionality reduction algorithms are widely used in numerous domains, including for recognition, segmentation, tracking and visualization. However, despite their popularity, these algorithms suffer from a major limitation known…

Machine Learning · Computer Science 2018-01-03 Yochai Blau , Tomer Michaeli

A generalized divergence theorem is established allowing for domains with inner boundaries. The normal trace of a rough integrand is not a Radon measure; rather, the boundary integral is expressed via a surface functional continuous with…

Analysis of PDEs · Mathematics 2025-10-29 Thomas Ruf

The significance of the broken ray transform (BRT) is due to its occurrence in a number of modalities spanning optical, x-ray, and nuclear imaging. When data are indexed by the scatter location, the BRT is both linear and shift invariant.…

Signal Processing · Electrical Eng. & Systems 2019-08-07 Michael R. Walker , Joseph A. O'Sullivan

We present an analysis of a novel spherical Radon transform, $R$, which defines the integrals of a function, $f$, in $\mathbb{R}^n$ over spheres with arbitrary center ($\mathbf{y}$) and radii, $r(\mathbf{y})$, which vary smoothly with…

Functional Analysis · Mathematics 2026-03-02 James W. Webber , Eric Todd Quinto

We present a novel approach for the inverse problem in electrical impedance tomography based on regularized quadratic regression. Our contribution introduces a new formulation for the forward model in the form of a nonlinear integral…

Geophysics · Physics 2012-05-29 Nick Polydorides , Alireza Aghasi , Eric L. Miller

Any even function defined on 2-sphere is reconstructed from its integrals over big circles by means of the classical Funk formula. For the non-geodesic Funk transform on the sphere of arbitrary dimension, there is the explicit inversion…

Functional Analysis · Mathematics 2017-11-29 Victor Palamodov