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We investigate $(0,1)$-matrices that are {\em convex}, which means that the ones are consecutive in every row and column. These matrices occur in discrete tomography. The notion of ranked essential sets, known for permutation matrices, is…

Combinatorics · Mathematics 2021-01-13 Richard A. Brualdi , Geir Dahl

This paper presents an alternate choice of computing the convex hulls (CHs) for planar point sets. We firstly discard the interior points and then sort the remaining vertices by x- / y- coordinates separately, and later create a group…

Computational Geometry · Computer Science 2013-09-02 Gang Mei , John C. Tipper , Nengxiong Xu

In this paper, we present a variant of the circumcenter method for the Convex Feasibility Problem (CFP), ensuring finite convergence under a Slater assumption. The method replaces exact projections onto the convex sets with projections onto…

Optimization and Control · Mathematics 2024-10-10 Roger Behling , Yunier Bello-Cruz , Alfredo Iusem , Di Liu , Luiz-Rafael Santos

We consider the Tarski--Bang problem about covering of convex bodies by planks. The results of this kind give a lower bound on the sum of widths of planks (regions between a pair of parallel hyperplanes) covering a given convex body.…

Metric Geometry · Mathematics 2020-02-18 Arseniy Akopyan , Roman Karasev , Fedor Petrov

The scattering of light observed through the turbid underwater channel is often regarded as the leading challenge when designing underwater electro-optical imaging systems. There have been many approaches to address the effects of…

Optics · Physics 2018-04-17 Chensheng Wu , Robert Lee , Christopher C. Davis

Symbiotic stars are binary systems where a white dwarf (WD) accretes material from the wind of an evolved, late-type companion. X-ray-emitting symbiotic systems are classified into $\alpha$, $\beta$, $\delta$, and $\beta/\delta$ types,…

High Energy Astrophysical Phenomena · Physics 2025-10-15 Jesús A. Toalá , Diego A. Vasquez-Torres

We propose a new modeling approach for scatter estimation and descattering in polyenergetic X-ray computed tomography (CT) based on fitting models to local neighborhoods of a training set. X-ray CT is widely used in medical and industrial…

Image and Video Processing · Electrical Eng. & Systems 2021-09-30 Michael T. McCann , Marc L. Klasky , Jennifer L. Schei , Saiprasad Ravishankar

Let $X$ be a perfectoid space with tilt $X^\flat$. We construct a canonical map $\theta:\operatorname{Pic} X^\flat\to\lim\operatorname{Pic} X$ where the (inverse) limit is taken over the $p$-power map, and show that $\theta$ is an…

Algebraic Geometry · Mathematics 2022-02-24 Gabriel Dorfsman-Hopkins

In this paper we develop a geometric approach to convex subdifferential calculus in finite dimensions with employing some ideas of modern variational analysis. This approach allows us to obtain natural and rather easy proofs of basic…

Optimization and Control · Mathematics 2015-10-06 Boris Mordukhovich , Nguyen Mau Nam

We continue the development of the study of the equisingularity of isolated singularities, in the determinantal case. This version of the paper includes a substantial amount of new material (76% larger). The new material introduces the idea…

Complex Variables · Mathematics 2016-01-05 Terence Gaffney , Antoni Rangachev

We show that every tiling of a convex set in the Euclidean plane $\mathbb{R}^2$ by equilateral triangles of mutually different sizes contains arbitrarily small tiles. The proof is purely elementary up to the discussion of one family of…

Metric Geometry · Mathematics 2017-11-27 Christian Richter , Melchior Wirth

We investigate the convex hulls of the eight dihedral symmetry classes of $n \times n$ alternating sign matrices, i.e., ASMs invariant under a subgroup of the symmetry group of the square. Extending the prefix-sum description of the ASM…

Combinatorics · Mathematics 2026-02-23 Péter Madarasi

This project aims to break down large pathology images into small tiles and then cluster those tiles into distinct groups without the knowledge of true labels, our analysis shows how difficult certain aspects of clustering tumorous and…

Image and Video Processing · Electrical Eng. & Systems 2020-12-29 Mostafa Ibrahim , Kevin Bryson

The classical method of determining the atomic structure of complex molecules by analyzing diffraction patterns is currently undergoing drastic developments. Modern techniques for producing extremely bright and coherent X-ray lasers allow a…

Biomolecules · Quantitative Biology 2015-10-12 Tomas Ekeberg , Stefan Engblom , Jing Liu

In this thesis, a new approach for constructing subdivision algorithms for generalized quadratic and cubic B-spline subdivision for subdivision surfaces and volumes is presented. First, a catalog of quality criteria for these subdivision…

Computational Geometry · Computer Science 2025-07-29 Alexander Dietz

We study geometric variations of the discriminating code problem. In the \emph{discrete version} of the problem, a finite set of points $P$ and a finite set of objects $S$ are given in $\mathbb{R}^d$. The objective is to choose a subset…

Computational Geometry · Computer Science 2023-06-30 Sanjana Dey , Florent Foucaud , Subhas C Nandy , Arunabha Sen

This work describes and demonstrates the operation of a virtual X-ray algorithm operating on finite-element post-processing results which allows for higher polynomial orders in geometry representation as well as density distribution. A…

Computational Engineering, Finance, and Science · Computer Science 2021-05-07 Maximilian Bittens

Starting from the classical results of Shubnikov and Zamorzayev, computer models of shapes are implemented, which allow to visualize the action of discrete subgroups of continuous topological groups. The action is visualize by performing…

Metric Geometry · Mathematics 2019-03-15 Alexander S. Prokhoda

Our main result states that whenever we have a non-Euclidean norm $\|\cdot\|$ on a two-dimensional vector space $X$, there exists some $x\neq 0$ such that for every $\lambda\neq 1, \lambda>0$, there exist $y, z\in X$ verifying that…

Metric Geometry · Mathematics 2024-02-09 Javier Cabello Sánchez , Adrián Gordillo-Merino

Automated detection and segmentation of surgical devices, such as catheters or wires, in X-ray fluoroscopic images have the potential to enhance image guidance in minimally invasive heart surgeries. In this paper, we present a convolutional…

Computer Vision and Pattern Recognition · Computer Science 2025-03-05 Lin Xi , Yingliang Ma , Ethan Koland , Sandra Howell , Aldo Rinaldi , Kawal S. Rhode
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