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We study the problem of covering R^d by overlapping translates of a convex body P, such that almost every point of R^d is covered exactly k times. Such a covering of Euclidean space by translations is called a k-tiling. The investigation of…

Combinatorics · Mathematics 2011-03-17 Nick Gravin , Sinai Robins , Dmitry Shiryaev

We prove a Santal\'{o} and a reverse Santal\'{o} inequality for the polarity transform, which was recently re-discovered by Artstein-Avidan and Milman, in the class consisting of (even) log-concave functions attaining their maximal value 1…

Functional Analysis · Mathematics 2013-09-12 Shiri Artstein-Avidan , Boaz Slomka

The goal of this paper is to study convex lattice sets by the discrete Legendre transform. The definition of the polar of convex lattice sets in $\mathbb{Z}^n$ is provided. It is worth mentioning that the polar of convex lattice sets have…

Metric Geometry · Mathematics 2024-05-29 Tingting He , Lin Si

The centerpoint theorem is a well-known and widely used result in discrete geometry. It states that for any point set $P$ of $n$ points in $\mathbb{R}^d$, there is a point $c$, not necessarily from $P$, such that each halfspace containing…

Computational Geometry · Computer Science 2018-10-25 Alexander Pilz , Patrick Schnider

In a locally finite tiling of n-dim Euclidean space by convex polytopes, each point of the space is either a vertex of at least two tiles, or no vertex at all.

Metric Geometry · Mathematics 2007-10-26 D. Frettlöh , A. Glazyrin

We study two notions. One is that of spindle convexity. A set of circumradius not greater than one is spindle convex if, for any pair of its points, it contains every short circular arc of radius at least one, connecting them. The other…

Metric Geometry · Mathematics 2011-10-20 Karoly Bezdek , Zsolt Langi , Marton Naszodi , Peter Papez

We study intersections of projective convex sets in the sense of Steinitz. In a projective space, an intersection of a nonempty family of convex sets splits into multiple connected components each of which is a convex set. Hence, such an…

Metric Geometry · Mathematics 2010-05-12 Takahisa Toda

A packing of translates of a convex body in the $d$-dimensional Euclidean space $\mathbb{E}^d$ is said to be totally separable if any two packing elements can be separated by a hyperplane of $\mathbb{E}^{d}$ disjoint from the interior of…

Metric Geometry · Mathematics 2020-02-12 Károly Bezdek , Zsolt Lángi

We prove that there is no d such that all finite projective planes can be represented by convex sets in R^d, answering a question of Alon, Kalai, Matousek, and Meshulam. Here, if P is a projective plane with lines l_1,...,l_n, a…

Combinatorics · Mathematics 2009-08-28 Martin Tancer

Polytopes are the basic finite data structures for convex sets: they appear as feasible regions in linear optimization, as geometric summaries in algorithms, and as random objects in stochastic geometry. A natural geometric question is…

Metric Geometry · Mathematics 2026-03-10 Steven Hoehner

The characterization of Kirkwood-Dirac (KD) classicality or non-classicality is very important in quantum information processing. In general, the set of KD classical states with respect to two bases is not a convex polytope[J. Math. Phys.…

Quantum Physics · Physics 2024-10-14 Ying-Hui Yang , Shuang Yao , Shi-Jiao Geng , Xiao-Li Wang , Pei-Ying Chen

Using equivariant topology, we prove that it is always possible to find $n$ points in the $d$-dimensional faces of a $nd$-dimensional convex polytope $P$ so that their center of mass is a target point in $P$. Equivalently, the $n$-fold…

Metric Geometry · Mathematics 2014-06-06 Michael Gene Dobbins

We address the problem of constructing elliptic polytopes in R^d, which are convex hulls of finitely many two-dimensional ellipses with a common center. Such sets arise in the study of spectral properties of matrices, asymptotics of long…

Numerical Analysis · Mathematics 2021-07-07 Thomas Mejstrik , Vladimir Yu. Protasov

For a finite point set $P \subset \mathbb{R}^d$, denote by $\text{diam}(P)$ the ratio of the largest to the smallest distances between pairs of points in $P$. Let $c_{d, \alpha}(n)$ be the largest integer $c$ such that any $n$-point set $P…

Combinatorics · Mathematics 2025-01-30 Boris Bukh , Zichao Dong

Let $K$ and $L$ be two convex bodies in ${\mathbb R^4}$, such that their projections onto all $3$-dimensional subspaces are directly congruent. We prove that if the set of diameters of the bodies satisfy an additional condition and some…

Metric Geometry · Mathematics 2015-09-30 M. Angeles Alfonseca , Michelle Cordier , Dmitry Ryabogin

The inverse problem of diffraction theory in essence amounts to the reconstruction of the atomic positions of a solid from its diffraction image. From a mathematical perspective, this is a notoriously difficult problem, even in the…

Metric Geometry · Mathematics 2009-02-23 Uwe Grimm , Michael Baake

Let $f_i(P)$ denote the number of $i$-dimensional faces of a convex polytope $P$. Furthermore, let $S(n,d)$ and $C(n,d)$ denote, respectively, the stacked and the cyclic $d$-dimensional polytopes on $n$ vertices. Our main result is that for…

Combinatorics · Mathematics 2007-05-23 Anders Björner

The classical H. Poincar\'{e} Center-Focus problem asks about the characterization of planar polynomial vector fields such that all their integral trajectories are closed curves whose interiors contain a fixed point, a {\em center}. This…

Dynamical Systems · Mathematics 2007-05-23 Alexander Brudnyi

The notion of center of mass, which is very useful in kinematics, proves to be very handy in geometry (see [1]-[2]). Countless applications of center of mass to geometry go back to Archimedes. Unfortunately, the center of mass cannot be…

Metric Geometry · Mathematics 2024-02-14 Askold Khovanskii

We construct a compact convex generating set $\mathcal{C}_n$ of the moduli set of closed connected projective special real manifolds of fixed dimension $n$. We show that a closed connected projective special real manifold corresponds to an…

Differential Geometry · Mathematics 2019-07-17 David Lindemann