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Related papers: X-Ray Transform in Asymptotically Conic Spaces

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Recently, several new characteristics have been introduced to describe null geodesic structure of strong gravitational field, such as photon regions, transversely trapping surfaces and some generalizations. They give an alternative and…

General Relativity and Quantum Cosmology · Physics 2019-11-13 D. V. Gal'tsov , K. V. Kobialko

Optical surfaces represented by second-degree polynomials (quadratic or conics) are ubiquitous in optics. We revisit the equations of the conic shapes in the context of grazing incidence optics, gathering together the curves commonly used…

Optics · Physics 2024-06-07 Manuel Sanchez del Rio , Kenneth Goldberg

We study the problem of proper discretizing and sampling issues related to geodesic X-ray transforms on simple surfaces, and illustrate the theory on simple geodesic disks of constant curvature. Given a notion of band limit on a function,…

Analysis of PDEs · Mathematics 2022-12-07 François Monard , Plamen Stefanov

Given a Lorentzian manifold, the light ray transform of a function is its integrals along null geodesics. This paper is concerned with the injectivity of the light ray transform on functions and tensors, up to the natural gauge for the…

Analysis of PDEs · Mathematics 2023-05-10 Ali Feizmohammadi , Joonas Ilmavirta , Lauri Oksanen

Sharp isoperimetric inequalities for the sine transform of even isotropic measures are established. The corresponding reverse inequalities are obtained in an asymptotically optimal form. These new inequalities have direct applications to…

Metric Geometry · Mathematics 2012-08-01 Gabriel Maresch , Franz E. Schuster

Complex and interesting electromagnetic behavior can be found in spaces with non-flat topology. When considering the properties of an electromagnetic medium under an arbitrary coordinate transformation an alternative interpretation presents…

Optics · Physics 2009-11-13 D. Schurig , J. B. Pendry , D. R. Smith

In this paper we consider the geodesic X-ray transform with attenuation coefficient as a combination of smooth complex function and 1-form. We show that attenuated X-ray transform applied to the pair of tensors is injective modulo the…

Differential Geometry · Mathematics 2017-03-07 Yernat M. Assylbekov

Let $g$ be a Riemannian metric for $\mathbf{R}^d$ ($d\geq 3$) which differs from the Euclidean metric only in a smooth and strictly convex bounded domain $M$. The lens rigidity problem is concerned with recovering the metric $g$ inside $M$…

Differential Geometry · Mathematics 2017-02-28 Gang Bao , Hai Zhang

In this article we study the linearized anisotropic Calder\'on problem on a compact Riemannian manifold with boundary. This problem amounts to showing that products of pairs of harmonic functions of the manifold form a complete set. We…

Analysis of PDEs · Mathematics 2020-09-15 Katya Krupchyk , Tony Liimatainen , Mikko Salo

Geodesic metric spaces support a variety of averaging constructions for given finite sets. Computing such averages has generated extensive interest in diverse disciplines. Here we consider the inverse problem of recognizing computationally…

Optimization and Control · Mathematics 2024-06-07 Ariel Goodwin , Adrian S. Lewis , Genaro Lopez-Acedo , Adriana Nicolae

In this paper, we consider the inverse problem of determining an unknown function defined in three space dimensions from its geodesic X-ray transform. The standard X-ray transform is defined on the Euclidean metric and is given by the…

Numerical Analysis · Mathematics 2018-04-27 Tak Shing Au Yeung , Eric T. Chung , Gunther Uhlmann

Representing graphs as sets of node embeddings in certain curved Riemannian manifolds has recently gained momentum in machine learning due to their desirable geometric inductive biases, e.g., hierarchical structures benefit from hyperbolic…

Machine Learning · Computer Science 2020-06-09 Calin Cruceru , Gary Bécigneul , Octavian-Eugen Ganea

We use geometric measure theory to introduce the notion of asymptotic cones associated with a singular subspace of a Riemannian manifold. This extends the classical notion of asymptotic directions usually defined on smooth submanifolds. We…

Differential Geometry · Mathematics 2015-01-13 Xiang Sun , Jean-Marie Morvan

This PhD dissertation is concerned with integral geometric inverse problems. The geodesic ray transform is an operator that encodes the line integrals of a function along geodesics. The dissertation establishes many conditions when such…

Differential Geometry · Mathematics 2020-10-23 Jesse Railo

In this paper, we study the topology of complete noncompact Riemannian manifolds with asymptotically nonnegative Ricci curvature. We show that a complete noncompact manifold with asymptoticaly nonnegative Ricci curvature and sectional…

Differential Geometry · Mathematics 2008-09-29 Bazanfare Mahaman

In this short paper we introduce a variant of the approach to inverting the X-ray transform that originated in the author's work with Uhlmann. The new method is based on semiclassical analysis and eliminates the need for using sufficiently…

Differential Geometry · Mathematics 2020-12-29 András Vasy

We study the X-ray transform over a generic family of smooth curves in $\mathbb{R}^2$ with a Riemannian metric $g$. We show that the singularities cannot be recovered from local data in the presence of conjugate points, and therefore…

Analysis of PDEs · Mathematics 2022-04-05 Yang Zhang

Coordinate-transformation approaches to invisibility cloaking rely on the design of an anisotropic, spatially inhomogeneous "transformation medium" capable of suitably re-routing the energy flux around the region to conceal without causing…

Optics · Physics 2015-05-13 Giuseppe Castaldi , Ilaria Gallina , Vincenzo Galdi

We prove a Krieger like embedding theorem for asymptotically expansive systems with the small boundary property. We show that such a system $(X; T)$ embeds in the $K$-full shift with $h_{top}(T) < \log K $ and $\sharp Per_n(X; T) \leq…

Dynamical Systems · Mathematics 2017-05-25 David Burguet

We introduce anti-invariant Riemannian submersions from cosymplectic manifolds onto Riemannian manifolds. We survey main results of anti-invariant Riemannian submersions defined on cosymplectic manifolds. We investigate necessary and…

Differential Geometry · Mathematics 2013-09-11 C. Murathan , I. Küpeli Erken