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Related papers: Admissible Complexes for the Projective X-Ray Tran…

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We consider random fields admitting a spectral representation with infinitely divisible integrator and prove some of their properties.

Probability · Mathematics 2010-10-26 Wolfgang Karcher

Recovering a function from its integrals over circular cones recently gained significance because of its relevance to novel medical imaging technologies such emission tomography using Compton cameras. In this paper we investigate the case…

Numerical Analysis · Mathematics 2016-06-14 Daniela Schiefeneder , Markus Haltmeier

We provide formulas for projectors onto a polyhedral set, i.e. the intersection of a finite number of halfspaces. To this aim we formulate the problem of finding the projection as a convex optimization problem and we solve explicitly…

Optimization and Control · Mathematics 2017-04-20 Krzysztof E. Rutkowski

This paper introduces the `Projectron' as a new neural network architecture that uses Radon projections to both classify and represent medical images. The motivation is to build shallow networks which are more interpretable in the medical…

Computer Vision and Pattern Recognition · Computer Science 2019-04-02 Aditya Sriram , Shivam Kalra , H. R. Tizhoosh

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

Novel analysis of finite dimensional Hilbert space is outlined. The approach bypasses general, inherent, difficulties present in handling angular variables in finite dimensional problems: The finite dimensional, d, Hilbert space operators…

Quantum Physics · Physics 2016-11-26 M. Revzen

We introduce a technique for recovering a sufficiently smooth function from its ray transform over a wide class of curves in a general region of Euclidean space. The method is based on a complexification of the underlying vector fields…

Complex Variables · Mathematics 2010-11-17 Nicholas Hoell , Guillaume Bal

We show that on simple surfaces the geodesic ray transform acting on solenoidal symmetric tensor fields of arbitrary order is injective. This solves a long standing inverse problem in the two-dimensional case.

Differential Geometry · Mathematics 2012-11-13 Gabriel P. Paternain , Mikko Salo , Gunther Uhlmann

We show injectivity of the X-ray transform and the $d$-plane Radon transform for distributions on the $n$-torus, lowering the regularity assumption in the recent work by Abouelaz and Rouvi\`ere. We also show solenoidal injectivity of the…

Differential Geometry · Mathematics 2016-06-21 Joonas Ilmavirta

We prove for the first time a pointwise lower estimate of the normal injectivity radius of an embedded hypersurface in an arbitrary Riemannian manifold. Main applications include: (i) a pointwise lower estimate of the graphing radius of a…

Differential Geometry · Mathematics 2025-11-26 Sebastian Boldt , Batu Güneysu , Stefano Pigola

The authors give a complete classification of projective threefolds admitting a holomorphic normal projective connection. Moreover, they prove a general structure theorem on complex projective manifolds admitting a holomorphic normal…

Algebraic Geometry · Mathematics 2007-05-23 Priska Jahnke , Ivo Radloff

Let $\bbK=\mathbb R, \mathbb C, \mathbb H$ be the field of real, complex or quaternionic numbers and $M_{p, q}(\bbK)$ the vector space of all $p\times q$-matrices. Let $X$ be the matrix unit ball in $M_{n-r, r}(\bbK)$ consisting of…

Functional Analysis · Mathematics 2007-11-12 Genkai Zhang

We study a particular broken ray transform on the Euclidean unit square and establish injectivity and stability for $C_{0}^{2}$ perturbations of the constant unit weight. Given an open subset $E$ of the boundary, we measure the attenuation…

Analysis of PDEs · Mathematics 2013-06-13 Mark Hubenthal

We consider the problem of projecting a convex set onto a subspace, or equivalently formulated, the problem of computing a set obtained by applying a linear mapping to a convex feasible set. This includes the problem of approximating convex…

Optimization and Control · Mathematics 2024-12-11 Gabriela Kováčová , Birgit Rudloff

Consider a finite morphism f:X -> Y of smooth projective varieties over a finite field k. Suppose X is the vanishing locus in projective N-space of at most r forms of degree at most d. We show there is a constant C, depending only on N, r,…

Algebraic Geometry · Mathematics 2020-02-27 Jeff Achter

Finite field transforms have many applications and, in many cases, can be implemented with a low computational complexity. In this paper, the Z Transform over a finite field is introduced and some of its properties are presented.

Number Theory · Mathematics 2018-01-26 R. M. Campello de Souza , H. M. de Oliveira , D. Silva

We study the projections in vector spaces over finite fields. We prove finite fields analogues of the bounds on the dimensions of the exceptional sets for Euclidean projection mapping. We provide examples which do not have exceptional…

Classical Analysis and ODEs · Mathematics 2017-07-31 Changhao Chen

We consider complex projective space with its Fubini-Study metric and the X-ray transform defined by integration over its geodesics. We identify the kernel of this transform acting on symmetric tensor fields.

Differential Geometry · Mathematics 2011-08-09 Michael Eastwood , Hubert Goldschmidt

We introduce a technique for recovering a sufficiently smooth function from its ray transform over a wide class of curves in a general region of Euclidean space. The method is based on a complexification of the underlying vector fields…

Complex Variables · Mathematics 2010-11-12 Nicholas Hoell , Guillaume Bal

Consider a finite-dimensional real vector space equipped with a finite group acting unitarily on it. We address the general problem of constructing Euclidean stable embeddings of the quotient space of orbits. Our approach is based on…

Representation Theory · Mathematics 2025-08-15 Radu Balan , Efstratios Tsoukanis