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Let $K$ be a convex body in $\mathbb{R} ^d$, with $d = 2,3$. We determine sharp sufficient conditions for a set $E$ composed of $1$, $2$, or $3$ points of ${\rm bd}K$, to contain at least one endpoint of a diameter of $K$ (for $d=2,3$). We…

Metric Geometry · Mathematics 2019-10-28 Jin-ichi Itoh , Costin Vîlcu , Liping Yuan , Tudor Zamfirescu

For a two-dimensional convex body, the Kovner-Besicovitch measure of symmetry is defined as the volume ratio of the largest centrally symmetric body contained inside the body to the original body. A classical result states that the…

Metric Geometry · Mathematics 2026-03-25 Ritesh Goenka , Kenneth Moore , Wen Rui Sun , Ethan Patrick White

We extend to arbitrary finite $n$ the notion of immobilization of a convex body $O$ in $R^n$ by a finite set of points $P$ in the boundary of $O$. Because of its importance for this problem, necessary and sufficient conditions are found for…

Metric Geometry · Mathematics 2018-10-29 Anthony David Gilbert , Saul Hannington Nsubuga

Let $\Omega \subset \mathbb{R}^{d}$ be a convex body with everywhere positive curvature except at the origin and with the boundary $\partial \Omega$ as the graph of the function $y=|x|^{\gamma}$ in a neighborhood of the origin with $\gamma…

Number Theory · Mathematics 2019-04-08 Bianca Gariboldi

This work proposes a new formulation to the long-standing problem of convex decomposition through learning feature fields, enabling the first feed-forward model for open-world convex decomposition. Our method produces high-quality…

Computer Vision and Pattern Recognition · Computer Science 2026-03-11 Yuezhi Yang , Qixing Huang , Mikaela Angelina Uy , Nicholas Sharp

Bayesian Networks (BNs) are useful tools giving a natural and compact representation of joint probability distributions. In many applications one needs to learn a Bayesian Network (BN) from data. In this context, it is important to…

Machine Learning · Computer Science 2012-07-02 Or Zuk , Shiri Margel , Eytan Domany

We study the fundamental problem of learning with respect to the squared loss in a convex class. The state-of-the-art sample complexity estimates in this setting rely on Rademacher complexities, which are generally difficult to control. We…

Statistics Theory · Mathematics 2025-02-24 Daniel Bartl , Shahar Mendelson

The purpose of this paper is to study the reflections of a convex body. In particular, we are interested in orthogonal reflections of its sections that can be extended to reflections of the whole body. For this reason, we need to study the…

Metric Geometry · Mathematics 2022-08-08 Jorge L. Arocha , Javier Bracho , Luis Montejano

We present an improved algorithm for {\em quasi-properly} learning convex polyhedra in the realizable PAC setting from data with a margin. Our learning algorithm constructs a consistent polyhedron as an intersection of about $t \log t$…

Machine Learning · Computer Science 2021-11-03 Lee-Ad Gottlieb , Eran Kaufman , Aryeh Kontorovich , Gabriel Nivasch

This paper addresses the fundamental question of when convex sets remain disjoint after random projection. We provide an analysis using ideas from high-dimensional convex geometry. For ellipsoids, we provide a bound in terms of the distance…

Machine Learning · Computer Science 2014-04-14 Afonso S. Bandeira , Dustin G. Mixon , Benjamin Recht

We consider the problem of multi-class classification, where a stream of adversarially chosen queries arrive and must be assigned a label online. Unlike traditional bounds which seek to minimize the misclassification rate, we minimize the…

Machine Learning · Computer Science 2021-11-17 Guru Guruganesh , Allen Liu , Jon Schneider , Joshua Wang

We consider systems of linear partial differential equations, which contain only second and first derivatives in the $x$ variables and which are uniformly parabolic in the sense of Petrovski\v{\i} in the layer ${\mathbb R}^n\times [0,T]$.…

Analysis of PDEs · Mathematics 2014-03-10 Gershon Kresin , Vladimir Maz'ya

The complexity of a learning task is increased by transformations in the input space that preserve class identity. Visual object recognition for example is affected by changes in viewpoint, scale, illumination or planar transformations.…

Computer Vision and Pattern Recognition · Computer Science 2017-03-16 Andrea Tacchetti , Stephen Voinea , Georgios Evangelopoulos

{We show in this paper that two normal elliptic sections through every point of the boundary of a smooth convex body essentially characterize an ellipsoid and furthermore, that four different pairwise non-tangent elliptic sections through…

Metric Geometry · Mathematics 2014-08-26 Isaac Arelio , Luis Montejano

Most existing distance metric learning methods assume perfect side information that is usually given in pairwise or triplet constraints. Instead, in many real-world applications, the constraints are derived from side information, such as…

Machine Learning · Computer Science 2012-03-19 Kaizhu Huang , Rong Jin , Zenglin Xu , Cheng-Lin Liu

Given a convex body C in R^d containing the origin in its interior and a real number tau > 1 we seek to construct a polytope P in C with as few vertices as possible such that C in tau P. Our construction is nearly optimal for a wide range…

Metric Geometry · Mathematics 2012-07-09 Alexander Barvinok

In this paper we prove a theorem that provides an upper bound for the density of packings of congruent copies of a given convex body in $\mathbb{R}^n$; this theorem is a generalization of the linear programming bound for sphere packings. We…

Metric Geometry · Mathematics 2019-11-07 Fernando Mário de Oliveira Filho , Frank Vallentin

$\newcommand{\eps}{\varepsilon}\newcommand{\tldO}{\widetilde{O}}$Consider the problem of constructing weak $\eps$-nets where the stabbing elements are lines or $k$-flats instead of points. We study this problem in the simplest setting where…

Computational Geometry · Computer Science 2022-05-05 Sariel Har-Peled , Mitchell Jones

We study upper bounds on the number of lattice points for convex bodies having their centroid at the origin. For the family of simplices as well as in the planar case we obtain best possible results. For arbitrary convex bodies we provide…

Metric Geometry · Mathematics 2015-05-26 Sören Lennart Berg , Martin Henk

High proved the following theorem. If the intersections of any two congruent copies of a plane convex body are centrally symmetric, then this body is a circle. In our paper we extend the theorem of High to spherical and hyperbolic planes.…

Metric Geometry · Mathematics 2016-01-19 J. Jerónimo-Castro , E. Makai