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This article presents the numerical verification and validation of several inversion algorithms for V-line transforms (VLTs) acting on symmetric 2-tensor fields in the plane. The analysis of these transforms and the theoretical foundation…

Numerical Analysis · Mathematics 2024-07-04 Gaik Ambartsoumian , Rohit Kumar Mishra , Indrani Zamindar

We prove injectivity and a support theorem for the X-ray transform on $2$-step nilpotent Lie groups with many totally geodesic $2$-dimensional flats. The result follows from a general reduction principle for manifolds with uniformly…

Differential Geometry · Mathematics 2016-01-19 Norbert Peyerimhoff , Evangelia Samiou

We consider the broken ray transform on Riemann surfaces in the presence of an obstacle, following earlier work of Mukhometov. If the surface has nonpositive curvature and the obstacle is strictly convex, we show that a function is…

Differential Geometry · Mathematics 2016-06-21 Joonas Ilmavirta , Mikko Salo

A unique inversion of the exponential X-ray transform of some class of symmetric 2-tensor field in a two dimensional strictly convex set is considered. The approach to inversion is based on the Cauchy problem for a Beltrami-like equation…

Analysis of PDEs · Mathematics 2024-12-06 David Omogbhe

We consider the proximal gradient method on Riemannian manifolds for functions that are possibly not geodesically convex. Starting from the forward-backward-splitting, we define an intrinsic variant of the proximal gradient method that uses…

Optimization and Control · Mathematics 2025-06-12 Ronny Bergmann , Hajg Jasa , Paula John , Max Pfeffer

Focus of this study is to explore some aspects of mathematical foundations for using complex manifolds as a model for space-time. More specifically, certain equations of motions have been derived as a Projective geodesic on a real manifold…

General Mathematics · Mathematics 2020-08-04 Swagatam Sen

In this paper, partly based on Zachos' PhD thesis, we show that the geodesic X-ray transform is stably invertible near infinity on a class of asymptotically conic manifolds which includes perturbations of Euclidean space. In particular…

Differential Geometry · Mathematics 2024-10-02 András Vasy , Evangelie Zachos

The windowed ray transform is a natural generalization of the "Analytic-Signal Transform" which is developed to extend arbitrary functions from $\RR^n$ to $\CC^n$. We present several inversion formulas here.

Functional Analysis · Mathematics 2013-11-25 Sunghwan Moon

Geometrical aspects of quantum computing are reviewed elementarily for non-experts and/or graduate students who are interested in both Geometry and Quantum Computation. In the first half we show how to treat Grassmann manifolds which are…

Quantum Physics · Physics 2007-05-23 Kazuyuki Fujii

We study Riemannian metrics on surfaces whose geodesic flows are superintegrable with one integral linear in momenta and one integral quartic in momenta. The main results of the work are local description of such metrics in terms of…

Mathematical Physics · Physics 2018-05-29 Pavel Novichkov

In this paper we consider the local X-ray transform for general flows. We extend the results on the local and global invertibility of the geodesic ray transform proved by Uhlmann and Vasy \cite{UV} to the X-ray transform for a general flow.…

Differential Geometry · Mathematics 2013-07-23 Hanming Zhou

We discuss pseudo-Riemannian metrics on 2-dimensional manifolds such that the geodesic flow admits a nontrivial integral quadratic in velocities. We construct local normal forms of such metrics. We show that these metrics have certain…

Mathematical Physics · Physics 2015-05-13 Alexey V. Bolsinov , Vladimir S. Matveev , Giuseppe Pucacco

We characterize the kernel of the mixed ray transform on simple $2$-dimensional Riemannian manifolds, that is, on simple surfaces for tensors of any order.

Differential Geometry · Mathematics 2018-08-07 Maarten V. de Hoop , Teemu Saksala , Jian Zhai

Efficiently accessing the information contained in non-linear and high dimensional probability distributions remains a core challenge in modern statistics. Traditionally, estimators that go beyond point estimates are either categorized as…

Methodology · Statistics 2021-07-06 Philipp Frank , Reimar Leike , Torsten A. Enßlin

We consider Calderon's inverse problem with partial data in dimensions $n \geq 3$. If the inaccessible part of the boundary satisfies a (conformal) flatness condition in one direction, we show that this problem reduces to the invertibility…

Analysis of PDEs · Mathematics 2016-01-20 Carlos E. Kenig , Mikko Salo

The algorithms given in Karney, J. Geodesy 87, 43-55 (2013), to compute geodesics on terrestrial ellipsoids are extended to apply to ellipsoids of revolution with arbitrary eccentricity. For the direct and inverse geodesic problems, this…

Geophysics · Physics 2025-10-28 Charles F. F. Karney

We consider the inverse problem of recovering a potential from the Dirichlet to Neumann map at a large fixed frequency on certain Riemannian manifolds. We extend the earlier result of [G. Uhlmann and Y. Wang, arXiv:2104.03477] to the case…

Analysis of PDEs · Mathematics 2023-09-01 Shiqi Ma , Suman Kumar Sahoo , Mikko Salo

Geodesics become an essential element of the geometry of a semi-Riemannian manifold. In fact, their differences and similarities with the (positive definite) Riemannian case, constitute the first step to understand semi-Riemannian Geometry.…

Differential Geometry · Mathematics 2010-03-23 Anna Maria Candela , Miguel Sánchez

We consider the boundary rigidity problem for asymptotically hyperbolic manifolds. We show injectivity of the X-ray transform in several cases and consider the non-linear inverse problem which consists of recovering a metric from boundary…

Differential Geometry · Mathematics 2017-09-18 C. Robin Graham , Colin Guillarmou , Plamen Stefanov , Gunther Uhlmann

This is a survey of the inverse spectral problem on (mainly compact) Riemannian manifolds, with or without boundary. The emphasis is on wave invariants: on how wave invariants have been calculated and how they have been applied to concrete…

Spectral Theory · Mathematics 2011-11-10 Steve Zelditch