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In this paper we show the invertibility of the geodesic X-ray transform on one forms and 2-tensors on asymptotically conic manifolds, up to the natural obstruction, allowing existence of certain kinds of conjugate points. We use the 1-cusp…

Differential Geometry · Mathematics 2022-12-06 Qiuye Jia , András Vasy

Existing ultrasound deconvolution approaches unrealistically assume, primarily for computational reasons, that the convolution model relies on a spatially invariant kernel and circulant boundary conditions. We discard both restrictions and…

Signal Processing · Electrical Eng. & Systems 2021-09-21 Mihai I. Florea , Adrian Basarab , Denis Kouamé , Sergiy A. Vorobyov

A central objective in inverse problems arising in integral geometry is to understand the kernel characterization, inversion formulas, stability estimates, range characterization, and unique continuation properties of integral transforms.…

Analysis of PDEs · Mathematics 2026-03-31 Rohit Kumar Mishra , Chandni Thakkar

The tensor decomposition addressed in this paper may be seen as a generalisation of Singular Value Decomposition of matrices. We consider general multilinear and multihomogeneous tensors. We show how to reduce the problem to a truncated…

Algebraic Geometry · Mathematics 2012-10-17 Alessandra Bernardi , Jerome Brachat , Pierre Comon , Bernard Mourrain

Assume that there exists a hypersurface singularity which cannot be resolved by iterated monoidal transformations in positive characteristic. We show that in the set of defining functions of hypersurface singularities which cannot be…

Algebraic Geometry · Mathematics 2010-06-21 Tohsuke Urabe

In this work we fully characterize the classes of matrix weights for which multilinear Calder\'on-Zygmund operators extend to bounded operators on matrix weighted Lebesgue spaces. To this end, we develop the theory of multilinear singular…

Functional Analysis · Mathematics 2024-12-20 Spyridon Kakaroumpas , Zoe Nieraeth

We show that any m-isometric tuples of commuting operators on a finite dimensional Hilbert space can be decomposed as a sum of a spherical isometry and a commuting nilpotent tuple. Our approach applies as well to tuples of algebraic…

Functional Analysis · Mathematics 2019-12-13 Trieu Le

Let~$X=\Po/\Gamma$ be an~$n$-punctured sphere, $n>3$. We introduce and study~$n-3$ deformation operators on the space of modular forms~$M_*(\Gamma)$ based on the classical theory of uniformizing differential equations and accessory…

Number Theory · Mathematics 2021-08-24 Gabriele Bogo

X-ray interaction with matter is an energy-dependent process that is contingent on the atomic structure of the constituent material elements. The most advanced models to capture this relationship currently rely on Monte Carlo (MC)…

Machine Learning · Computer Science 2023-07-11 Raziye Kubra Kumrular , Thomas Blumensath

We show how well known tools of algebraic geometry for the study of finite sets can be fruitfully applied to the study of Waring decompositions of symmetric tensors (forms). We mainly focus on the uniqueness of a given decomposition (the…

Algebraic Geometry · Mathematics 2018-07-03 Luca Chiantini

We introduce and study the notion of null manifold. This is a smooth manifold ${\mathcal N}$ endowed with a degenerate metric $\gamma$ with one-dimensional radical at every point. We also define the notion of ruled null manifold, which is a…

General Relativity and Quantum Cosmology · Physics 2024-02-13 Marc Mars

In this article, we establish that any symmetric $m$-tensor field can be recovered pointwise from partial data of the $k$-th weighted divergent ray transform for any $k \in \mathbb{Z}^{+} \cup\{0\}$. Using the unique continuation property…

Analysis of PDEs · Mathematics 2025-09-12 Shubham R. Jathar , Manas Kar , Venkateswaran P. Krishnan , Rahul Raju Pattar

This is an introductory survey, from a geometric perspective, on the Singular Value Decomposition (SVD) for real matrices, focusing on the role of the Terracini Lemma. We extend this point of view to tensors, we define the singular space of…

Algebraic Geometry · Mathematics 2015-03-25 Giorgio Ottaviani , Raffaella Paoletti

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

Matrix models with continuous symmetry are powerful tools for studying quantum gravity and holography. Tensor models have also found applications in holographic quantum gravity. Matrix models with discrete permutation symmetry have been…

High Energy Physics - Theory · Physics 2023-12-15 George Barnes , Adrian Padellaro , Sanjaye Ramgoolam

We study how iterated and composed completely positive maps act on operator-valued kernels. Each kernel is realized inside a single Hilbert space where composition corresponds to applying bounded creation operators to feature vectors. This…

Functional Analysis · Mathematics 2025-11-18 James Tian

We study a set of generalized V-line transforms, namely longitudinal, mixed, and transverse V-line transforms, of a symmetric $m$-tensor field in $\mathbb{R}^2$. The goal of this article is to recover a symmetric $m$-tensor field…

Analysis of PDEs · Mathematics 2025-02-10 Rahul Bhardwaj

Let $I_{m}$ denote the Euclidean ray transform acting on compactly supported symmetric $m$-tensor field distributions $f$, and $I_{m}^{*}$ be its formal $L^2$ adjoint. We study a unique continuation result for the normal operator…

Analysis of PDEs · Mathematics 2022-03-04 Divyansh Agrawal , Venkateswaran P. Krishnan , Suman Kumar Sahoo

The X-ray transform on a compact symmetric space M is here inverted by means of an explicit inversion formula. The proof uses the conjugacy of the minimal closed geodesics in M and of the maximally curved totally geodesic spheres in M,…

Representation Theory · Mathematics 2007-05-23 Sigurdur Helgason

We consider the decomposition of bounded linear operators on Hilbert spaces in terms of functions forming frames. Similar to the singular-value decomposition, the resulting frame decompositions encode information on the structure and…

Numerical Analysis · Mathematics 2021-05-26 Simon Hubmer , Ronny Ramlau