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Given $L$ a convex body, the $L_p$-Busemann Random Simplex Inequality is closely related to the centroid body $\Gamma_p L$ for $p=1$ and $2$, and only in these cases it can be proved using the $L_p$-Busemann-Petty centroid inequality. We…

Metric Geometry · Mathematics 2025-01-24 Julián Eduardo Haddad

We continue the study of intersection bodies of polytopes, focusing on the behavior of $IP$ under translations of $P$. We introduce an affine hyperplane arrangement and show that the polynomials describing the boundary of $I(P+t)$ can be…

Metric Geometry · Mathematics 2025-06-02 Marie-Charlotte Brandenburg , Chiara Meroni

The Busemann-Petty problem asks whether origin symmetric convex bodies in $\R^n$ with smaller hyperplane sections necessarily have smaller volume. The answer is affirmative if $n\leq 3$ and negative if $n\geq 4.$ We consider a class of…

Functional Analysis · Mathematics 2008-11-20 Marisa Zymonopoulou

The illumination number $I(K)$ of a convex body $K$ in Euclidean space $\mathbb{E}^d$ is the smallest number of directions that completely illuminate the boundary of a convex body. A cap body $K_c$ of a ball is the convex hull of a…

Metric Geometry · Mathematics 2026-05-01 Ilya Ivanov , Cameron Strachan

On a convex body in a Euclidean space, we introduce a new variational formulation for its Funk metric, a Finsler metric compatible with the tautological Finsler structure of the convex body. We generalize the metric on Teichmuller spaces…

Differential Geometry · Mathematics 2012-06-12 Sumio Yamada

Let $K\subset \mathbb{R}^n$ be a convex body, $n\geq 3$. We say that $K$ satisfies the Barker-Larman condition if there exists a ball $B$ in the interior of $K$ such that for every suppor hyperplane $\Pi$ of $B$, the section $\Pi \cap K$ is…

Metric Geometry · Mathematics 2025-11-21 E. Morales-Amaya

Existence of nicely bounded sections of two symmetric convex bodies K and L implies that the intersection of random rotations of K and L is nicely bounded. For L = subspace, this main result immediately yields the unexpected phenomenon: "If…

Functional Analysis · Mathematics 2016-12-23 Roman Vershynin

Employing the affine normal flow, we prove a stability version of the $p$-affine isoperimetric inequality for $p\geq1$ in $\mathbb{R}^2$ in the class of origin-symmetric convex bodies. That is, if $K$ is an origin-symmetric convex body in…

Differential Geometry · Mathematics 2013-03-28 Mohammad N. Ivaki

Let $d \ge 2$, and let $K \subset {\Bbb{R}}^d$ be a convex body containing the origin $0$ in its interior. In a previous paper we have proved the following. The body $K$ is $0$-symmetric if and only if the following holds. For each $\omega…

Metric Geometry · Mathematics 2015-07-07 E. Makai , H. Martini

We study touching cones of a (not necessarily closed) convex set in a finitedimensional real Euclidean vector space and we draw relationships to other concepts in Convex Geometry. Exposed faces correspond to normal cones by an antitone…

Metric Geometry · Mathematics 2016-05-17 Stephan Weis

In light of the log-Brunn-Minkowski conjecture, various attempts have been made to define the geometric mean of convex bodies. Many of these constructions are fairly complex and/or fail to satisfy some natural properties one would expect of…

Metric Geometry · Mathematics 2024-05-02 René Brandenberg , Florian Grundbacher

In this note we prove two ellipsoid characterization theorems. The first one is that if $K$ is a convex body in a normed space with unit ball $M$, and for any point $p \notin K$ and in any 2-dimensional plane $P$ intersecting $\inter K$ and…

Metric Geometry · Mathematics 2012-11-07 Z. Langi

Under mild assumptions on the kernel $K\ge0$, the non-local $K$-perimeter $P_K$ satisfies the monotonicity property on nested convex bodies, i.e., if $A\subset B\subset\mathbb{R}^n$ are two convex bodies, then $P_K(A)\le P_K(B)$. In this…

Metric Geometry · Mathematics 2023-09-21 Flavia Giannetti , Giorgio Stefani

This article belongs to the area of geometric tomography, which is the study of geometric properties of solids based on data about their sections and projections. We describe a new direction in geometric tomography where different…

Functional Analysis · Mathematics 2023-02-10 Apostolos Giannopoulos , Alexander Koldobsky , Artem Zvavitch

The generalized Busemann-Petty problem asks whether origin-symmetric convex bodies with lower-dimensional smaller sections necessarily have smaller volume. We study the weighted version of this problem corresponding to the physical…

Functional Analysis · Mathematics 2007-05-23 Rubin Boris

In this paper we study the class of so called `ball-bodies' in ${\mathbb R}^n$, given by intersections of translates of Euclidean unit balls (or, equivalently, summand of the Euclidean ball). We study the class along with the natural…

Metric Geometry · Mathematics 2025-05-20 Shiri Artstein-Avidan , Dan I. Florentin

While there is extensive literature on approximation of convex bodies by inscribed or circumscribed polytopes, much less is known in the case of generally positioned polytopes. Here we give upper and lower bounds for approximation of convex…

Probability · Mathematics 2021-03-03 Steven D. Hoehner , Carsten Schuett , Elisabeth M. Werner

The main goal of this paper is to present a series of inequalities connecting the surface area measure of a convex body and surface area measure of its projections and sections. We present a solution of a question from S. Campi, P.…

Metric Geometry · Mathematics 2017-08-29 Alexander Koldobsky , Christos Saroglou , Artem Zvavitch

The notion of ball convexity, considered in finite dimensional real Banach spaces, is a natural and useful extension of usual convexity; one replaces intersections of half-spaces by suitable intersections of balls. A subset $S$ of a normed…

Metric Geometry · Mathematics 2017-07-18 Thomas Jahn , Christian Richter , Horst Martini

Consider some convex body $K\subset\mathbb R^d$. Let $X_1,\dots, X_k$, where $k\leq d$, be random points independently and uniformly chosen in $K$, and let $\xi_k$ be a uniformly distributed random linear $k$-plane. We show that for…

Metric Geometry · Mathematics 2022-02-08 Alexander E. Litvak , Dmitry Zaporozhets