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We prove several new results around Gromov's waist theorem. We give a simple proof of Vaaler's theorem on sections of the unit cube using the Borsuk--Ulam--Crofton technique. We consider waists of real and complex projective spaces, flat…

Differential Geometry · Mathematics 2019-12-30 Arseniy Akopyan , Alfredo Hubard , Roman Karasev

Let $1\leq i \leq k < n$ be integers. We prove the following exact inequalities for any convex body $K\subset\mathbb{R}^n$ with centroid at the origin, and any $k$-dimensional subspace $E\subset \mathbb{R}^n$: \begin{align*} &V_i \big(…

Metric Geometry · Mathematics 2018-09-18 Matthew Stephen , Vladyslav Yaskin

We prove polarity duality for covering problems in Hilbert geometry. Let $G$ and $K$ be convex bodies in $\mathbb{R}^d$ where $G \subset \operatorname{int}(K)$ and $\operatorname{int}(G)$ contains the origin. Let $N^H_K(G,\alpha)$ and…

Metric Geometry · Mathematics 2026-04-28 Sunil Arya , David M. Mount

We provide a natural generalization of a geometric conjecture of F\'{a}ry and R\'{e}dei regarding the volume of the convex hull of $K \subset {\mathbb R}^n$, and its negative image $-K$. We show that it implies Godbersen's conjecture…

Metric Geometry · Mathematics 2014-08-12 S. Artstein-Avidan , K. Einhorn , D. Y. Florentin , Y. Ostrover

Is it true that a convex body $K$ being complete and reduced with respect to some gauge body $C$ is necessarily of constant width, that is, satisfies $K-K=\rho(C-C)$ for some $\rho>0$? We prove this implication for several cases including…

Metric Geometry · Mathematics 2016-02-26 René Brandenberg , Bernardo González Merino , Thomas Jahn , Horst Martini

We show that if the Gauss Image Measure of submeasure $\lambda$ via convex body $K$ agrees with the Gauss Image Measure of $\lambda$ via convex body $L$, then the radial Gauss Image maps of their duals, are equal to each other almost…

Metric Geometry · Mathematics 2023-05-04 Vadim Semenov

Given a warped product space $\mathbb{R} \times_{f} N$ with logarithmically convex warping function $f$, we prove a relative isoperimetric inequality for regions bounded between a subset of a vertical fiber and its image under an almost…

Geometric Topology · Mathematics 2010-09-23 Shawn Rafalski

We give an alternative proof of a recent result of Klartag on the existence of almost subgaussian linear functionals on convex bodies. If $K$ is a convex body in ${\mathbb R}^n$ with volume one and center of mass at the origin, there exists…

Functional Analysis · Mathematics 2007-05-23 Apostolos Giannopoulos , Alain Pajor , Grigoris Paouris

In this note, we prove the following inequality for the norm of a convex body $K$ in $\mathbb{R}^n$, $n\geq 2$: $N(K) \leq \frac{\pi^{\frac{n-1}{2}}}{2 \Gamma \left(\frac{n+1}{2}\right)}\cdot \operatorname{length} (\gamma) +…

Metric Geometry · Mathematics 2022-10-04 Yurii Nikonorov

We prove that if $K$ is a symmetric and isotropic convex body in $\mathbb{R}^n$, then $$\int_K\langle x,u\rangle^2\,dx\int_{K^\circ}\langle x,u\rangle^2\,dx\leq \left(\int_{B_2^n}\langle x,u\rangle^2\,dx\right)^2,\qquad\forall…

Metric Geometry · Mathematics 2026-05-26 Károly J. Böröczky , Konstantinos Patsalos , Christos Saroglou

In this note we examine the volume of the convex hull of two congruent copies of a convex body in Euclidean $n$-space, under some subsets of the isometry group of the space. We prove inequalities for this volume if the two bodies are…

Metric Geometry · Mathematics 2013-06-19 Ákos G. Horváth , Z. Lángi

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

We consider a functional $\mathcal F$ on the space of convex bodies in $\R^n$ defined as follows: ${\mathcal F}(K)$ is the integral over the unit sphere of a fixed continuous functions $f$ with respect to the area measure of the convex body…

Metric Geometry · Mathematics 2012-09-11 Andrea Colesanti , Daniel Hug , Eugenia Saorin Gomez

The aim of this paper is to study properties of sections of convex bodies with respect to different types of measures. We present a formula connecting the Minkowski functional of a convex symmetric body K with the measure of its sections.…

Metric Geometry · Mathematics 2007-05-23 Artem Zvavitch

We study the volume ratio between projections of two convex bodies. Given a high-dimensional convex body $K$ we show that there is another convex body $L$ such that the volume ratio between any two projections of fixed rank of the bodies…

Metric Geometry · Mathematics 2022-11-14 Daniel Galicer , Alexander E. Litvak , Mariano Merzbacher , Damián Pinasco

Let K be a closed bounded convex subset of $\Bbb R^n$; then by a result of the first author, which extends a classical theorem of Whitney there is a constant $w_m(K)$ so that for every continuous function f on K there is a polynomial $\phi$…

Functional Analysis · Mathematics 2007-05-23 Y. Brudnyi , N. J. Kalton

Let $K$ be an $n$-dimensional convex body. Define the difference body by $$ K-K= \{x-y \mid x,y \in K \}. $$ We estimate the volume of the section of $K-K$ by a linear subspace $F$ via the maximal volume of sections of $K$ parallel to $F$.…

Functional Analysis · Mathematics 2007-05-23 M. Rudelson

The Brunn-Minkowski Theory has seen several generalizations over the past century. Many of the core ideas have been generalized to measures. With the goal of framing these generalizations as a weighted Brunn-Minkowski theory, we prove the…

Functional Analysis · Mathematics 2023-09-28 Liudmyla Kryvonos , Dylan Langharst

Let $K$ be a convex body in $\mathbb R^n$. We prove that in small codimensions, the sections of a convex body through the centroid are quite symmetric with respect to volume. As a consequence of our estimates we give a positive answer to a…

Metric Geometry · Mathematics 2016-04-20 Matthieu Fradelizi , Mathieu Meyer , Vlad Yaskin

In the first part of this paper, we develop the theory of anisotropic curvature measures for convex bodies in the Euclidean space. It is proved that any convex body whose boundary anisotropic curvature measure equals a linear combination of…

Differential Geometry · Mathematics 2021-08-05 Ben Andrews , Yitao Lei , Yong Wei , Changwei Xiong