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Related papers: Slicing convex sets and measures by a hyperplane

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Many results in mass partitions are proved by lifting $\mathbb{R}^d$ to a higher-dimensional space and dividing the higher-dimensional space into pieces. We extend such methods to use lifting arguments to polyhedral surfaces. Among other…

Combinatorics · Mathematics 2021-09-09 Pablo Soberón , Yuki Takahashi

In this work we present a theorem regarding two convex bodies $K_1, K_2\subset \mathbb{R}^{n}$, $n\geq 3$, and two families of sections of them, given by two families of tangent planes of two spheres $S_i\subset \textrm{int}\textrm{ } K_i$,…

Metric Geometry · Mathematics 2025-08-21 Efren Morales-Amaya

The aim of this note is to give a sufficient condition for pairs of functions to have a convex separator when the underlying structure is a Cartan--Hadamard manifold, or more generally: a reduced Birkhoff--Beatley system. Some exotic…

Metric Geometry · Mathematics 2020-09-29 Mihály Bessenyei , Dávid Cs. Kertész , Rezső L. Lovas

Assume that $k \le d$ is a positive integer and $\C$ is a finite collection of convex bodies in $\R^d$. We prove a Helly type theorem: If for every subfamily $\C^*\subset \C$ of size at most $\max \{d+1,2(d-k+1)\}$ the set $\bigcap \C^*$…

Metric Geometry · Mathematics 2023-08-22 Imre Barany

In this paper we address the reverse isoperimetric inequality for convex bodies with uniform curvature constraints in the hyperbolic plane $\mathbb{H}^2$. We prove that the\textit{ thick $\lambda$-sausage} body, that is, the convex domain…

Metric Geometry · Mathematics 2025-10-07 Maria Esteban

For every hyperplane $H$ supporting a convex body $C$ in the hyperbolic space $\mathbb{H}^d$ we define the width of $C$ determined by $H$ as the distance between $H$ and a most distant ultraparallel hyperplane supporting $C$. We prove that…

Metric Geometry · Mathematics 2024-02-27 Marek Lassak

We initiate the study of convex geometry over ordered hyperfields. We define convex sets and halfspaces over ordered hyperfields, presenting structure theorems over hyperfields arising as quotients of fields. We prove hyperfield analogues…

Metric Geometry · Mathematics 2025-09-24 James Maxwell , Ben Smith

Gardner, Gronchi and Zong posed the problem to find a discrete analogue of M. Meyer's inequality bounding the volume of a convex body from below by the geometric mean of the volumes of its slices with the coordinate hyperplanes. Motivated…

Metric Geometry · Mathematics 2020-05-01 Ansgar Freyer , Martin Henk

If a convex body $K \subset \mathbb{R}^n$ is covered by the union of convex bodies $C_1, \ldots, C_N$, multiple subadditivity questions can be asked. Two classical results regard the subadditivity of the width (the smallest distance between…

Metric Geometry · Mathematics 2020-09-16 Alexey Balitskiy

Following ideas of Iriyeh and Shibata we give a short proof of the three-dimensional Mahler conjecture {\mf for symmetric convex bodies}. Our contributions include, in particular, simple self-contained proofs of their two key statements.…

Metric Geometry · Mathematics 2021-01-21 Matthieu Fradelizi , Alfredo Hubard , Mathieu Meyer , Edgardo Roldán-Pensado , Artem Zvavitch

We study the slices or sections of a convex polytope by affine hyperplanes. We present results on two key problems: First, we provide tight bounds on the maximum number of vertices attainable by a hyperplane slice of $d$-polytope (a sort of…

Combinatorics · Mathematics 2025-07-24 Jesús A. De Loera , Gyivan Lopez-Campos , Antonio J. Torres

We prove an estimate for arbitrary measure of sections of convex bodies. The proof is based on a stability result for intersection bodies.

Metric Geometry · Mathematics 2013-09-23 Alexander Koldobsky

We prove several results of the following type: any $d$ measures in $\mathbb R^d$ can be partitioned simultaneously into $k$ equal parts by a convex partition (this particular result is proved independently by Pablo Sober\'on). Another…

Metric Geometry · Mathematics 2013-06-17 R. N. Karasev

We introduce and prove the $n$-dimensional Pizza Theorem: Let $\mathcal{H}$ be a hyperplane arrangement in $\mathbb{R}^{n}$. If $K$ is a measurable set of finite volume, the {pizza quantity} of $K$ is the alternating sum of the volumes of…

Combinatorics · Mathematics 2022-02-11 Richard Ehrenborg , Sophie Morel , Margaret Readdy

Hadwiger's theorem is a Helly-type theorem involving common transversals to families of convex sets instead of common intersections. Subsequently, Pollack and Wenger identified a necessary and sufficient condition, called a consistent…

Combinatorics · Mathematics 2025-12-03 Ilani Axelrod-Freed , João Pedro Carvalho , Yuki Takahashi

This paper contains a new concept to measure the width and thickness of a convex body in the hyperbolic plane. We compare the known concepts with the new one and prove some results on bodies of constant width, constant diameter and given…

Metric Geometry · Mathematics 2020-12-01 Ákos G. Horváth

We prove a generalization of the hyperplane inequality for intersection bodies, where volume is replaced by an arbitrary measure $\mu$ with even continuous density and sections are of arbitrary dimension $n-k,\ 1\le k <n.$ If $K$ is a…

Metric Geometry · Mathematics 2011-08-15 Alexander Koldobsky , Dan Ma

Barker and Larman asked the following. Let $K' \subset {\Bbb{R}}^d$ be a convex body, whose interior contains a given convex body $K \subset {\Bbb{R}}^d$, and let, for all supporting hyperplanes $H$ of $K$, the $(d-1)$-volumes of the…

Metric Geometry · Mathematics 2016-02-03 E. Makai, , H. Martini

Equivariant "Ham Sandwich" Theorems are obtained for the finite subgroups G of the unit spheres S(F) in the classical algebras F = R, C, and H. Given any n F-valued mass distributions on F^n, it is shown that there exists a G-equivariant…

Combinatorics · Mathematics 2013-08-02 Steven Simon

Let T be the unit circle in the complex plane C. This paper proves the existence of analytic structure in a compact subset K of T X C^n, where K has so-called "lineally convex" or "hypoconvex" fibers over T. It also addresses a related…

Complex Variables · Mathematics 2007-05-23 Marshall A. Whittlesey