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We prove that if $(X,\mathsf{d},\mathfrak{m})$ is a metric measure space with $\mathfrak{m}(X)=1$ having (in a synthetic sense) Ricci curvature bounded from below by $K>0$ and dimension bounded above by $N\in [1,\infty)$, then the classic…

Metric Geometry · Mathematics 2019-05-08 Fabio Cavalletti , Andrea Mondino

The Brunn-Minkowski theory in convex geometry concerns, among other things, the volumes, mixed volumes, and surface area measures of convex bodies. We study generalizations of these concepts to Borel measures with density in…

Metric Geometry · Mathematics 2024-03-13 Matthieu Fradelizi , Dylan Langharst , Mokshay Madiman , Artem Zvavitch

In this paper we present new versions of the classical Brunn-Minkowski inequality for different classes of measures and sets. We show that the inequality \[ \mu(\lambda A + (1-\lambda)B)^{1/n} \geq \lambda \mu(A)^{1/n} +…

Probability · Mathematics 2015-07-10 Galyna Livshyts , Arnaud Marsiglietti , Piotr Nayar , Artem Zvavitch

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

We formulate a generalization of the volume conjecture for planar graphs. Denoting by <G, c> the Kauffman bracket of the graph G whose edges are decorated by real "colors" c, the conjecture states that, under suitable conditions, certain…

Geometric Topology · Mathematics 2014-03-11 Francesco Costantino , François Guéritaud , Roland van der Veen

We introduce a new volume definition on normed vector spaces. We show that the induced $k$-area functionals are convex for all $k$. In the particular case $k=2$, our theorem implies that Busemann's 2-volume density is convex, which was…

Differential Geometry · Mathematics 2015-09-24 Andreas Bernig

In [SZ], Soprunov and Zvavitch have translated the Bezout inequalities (from Algebraic Geometry) into inequalities of mixed volumes satisfied by the simplex. They conjecture this set of inequalities characterizes the simplex, among all…

Functional Analysis · Mathematics 2023-04-04 Maud Szusterman

It is proved that if $u_1,\ldots, u_n$ are vectors in ${\Bbb R}^k, k\le n, 1 \le p < \infty$ and $$r = ({1\over k} \sum ^n_1 |u_i|^p)^{1\over p}$$ then the volume of the symmetric convex body whose boundary functionals are $\pm u_1,\ldots,…

Metric Geometry · Mathematics 2016-09-06 Keith Ball , Alain Pajor

A classical result of Dowker (Bull. Amer. Math. Soc. 50: 120-122, 1944) states that for any plane convex body $K$, the areas of the maximum (resp. minimum) area convex $n$-gons inscribed (resp. circumscribed) in $K$ is a concave (resp.…

Metric Geometry · Mathematics 2024-02-08 Bushra Basit , Zsolt Lángi

Let $K$ and $L$ be two convex bodies in $\mathbb R^n$, $n\geq 2$, with $L\subset \text{int}\, K$. We say that $L$ is an equichordal body for $K$ if every chord of $K$ tangent to $L$ has length equal to a given fixed value $\lambda$. J.…

Metric Geometry · Mathematics 2026-02-03 Jesús Jerónimo-Castro , Francisco G. Jimenez-Lopez , Efrén Morales-Amaya

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

For a convex body $K\subset\R^n$, the $k$th projection function of $K$ assigns to any $k$-dimensional linear subspace of $\R^n$ the $k$-volume of the orthogonal projection of $K$ to that subspace. Let $K$ and $K_0$ be convex bodies in…

Metric Geometry · Mathematics 2007-05-23 Ralph Howard , Daniel Hug

Let $C\subset {\mathbb R}^n$ be a convex body. We introduce two notions of convexity associated to C. A set $K$ is $C$-ball convex if it is the intersection of translates of $C$, or it is either $\emptyset$, or ${\mathbb R}^n$. The $C$-ball…

Metric Geometry · Mathematics 2012-09-06 Zsolt Lángi , Márton Naszódi , István Talata

We provide general inequalities that compare the surface area S(K) of a convex body K in ${\mathbb R}^n$ to the minimal, average or maximal surface area of its hyperplane or lower dimensional projections. We discuss the same questions for…

Metric Geometry · Mathematics 2019-08-15 Apostolos Giannopoulos , Alexander Koldobsky , Petros Valettas

We survey results on the problem of covering the space ${\mathbb R}^n$, or a convex body in it, by translates of a convex body. Our main goal is to present a diverse set of methods. A theorem of Rogers is a central result, according to…

Metric Geometry · Mathematics 2016-03-16 Márton Naszódi

We show that the mixed volumes of arbitrary convex bodies are equal to mixed multiplicities of graded families of monomial ideals, and to normalized limits of mixed multiplicities of monomial ideals. This result evinces the close relation…

Commutative Algebra · Mathematics 2021-02-18 Yairon Cid-Ruiz , Jonathan Montaño

In this paper we prove the following Willmore-type inequality: On an unbounded closed convex set $K\subset\mathbb{R}^{n+1}$ $(n\ge 2)$, for any embedded hypersurface $\Sigma\subset K$ with boundary $\partial\Sigma\subset \partial K$…

Differential Geometry · Mathematics 2025-03-06 Xiaohan Jia , Guofang Wang , Chao Xia , Xuwen Zhang

We consider two well-known problems: upper bounding the volume of lower dimensional ellipsoids contained in convex bodies given their John ellipsoid, and lower bounding the volume of ellipsoids containing projections of convex bodies given…

Metric Geometry · Mathematics 2025-01-03 René Brandenberg , Florian Grundbacher

Various results are proved giving lower bounds for the $m$th intrinsic volume $V_m(K)$, $m=1,\dots,n-1$, of a compact convex set $K$ in ${\mathbb{R}}^n$, in terms of the $m$th intrinsic volumes of its projections on the coordinate…

Metric Geometry · Mathematics 2013-12-10 Stefano Campi , Richard J. Gardner , Paolo Gronchi

It is shown that the volume entropy of a Hilbert geometry associated to an $n$-dimensional convex body of class $C^{1,1}$ equals $n-1$. To achieve this result, a new projective invariant of convex bodies, similar to the centro-affine area,…

Differential Geometry · Mathematics 2010-05-21 Gautier Berck , Andreas Bernig , Constantin Vernicos