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In this paper, we verify the $\ell^p$ coarse Baum-Connes conjecture for open cones and show that the $K$-theory for $\ell^p$ Roe algebras of open cones are independent of $p\in[1,\infty)$. Combined with the result of T. Fukaya and S.-I.…

Operator Algebras · Mathematics 2022-03-22 Jianguo Zhang

Let $K \subset {\mathbb R}^2$ be an $o$-symmetric convex body, and $K^*$ its polar body. Then we have $|K|\cdot |K^*| \ge 8$, with equality if and only if $K$ is a parallelogram. ($| \cdot |$ denotes volume). If $K \subset {\mathbb R}^2$ is…

Metric Geometry · Mathematics 2015-07-07 K. J. Böröczky , E. Makai , M. Meyer , S. Reisner

We prove that the uniform probability measure $\mu$ on every $(n-k)$-dimensional projection of the $n$-dimensional unit cube verifies the variance conjecture with an absolute constant $C$ $$\textrm{Var}_\mu|x|^2\leq C \sup_{\theta\in…

Functional Analysis · Mathematics 2017-03-30 David Alonso-Gutiérrez , Julio Bernués

We generalize the ham sandwich theorem for the case of well separated measures. Given convex bodies $K_1,...,K_d$ in $\mathbb{R_d}$ and numbers $\alpha_1,...,\alpha_d \in [0, 1]$, we give a sufficient condition for existence and uniqueness…

Combinatorics · Mathematics 2010-11-01 Imre Barany , Alfredo Hubard , Jesus Jeronimo

The isotropic constant $L_K$ is an affine-invariant measure of the spread of a convex body $K$. For a $d$-dimensional convex body $K$, $L_K$ can be defined by $L_K^{2d} = \det(A(K))/(\mathrm{vol}(K))^2$, where $A(K)$ is the covariance…

Functional Analysis · Mathematics 2015-12-09 Luis Rademacher

We generalize the classical Hardy and Faber-Krahn inequalities to arbitrary functions on a convex body $\Omega \subset \mathbb{R}^n$, not necessarily vanishing on the boundary $\partial \Omega$. This reduces the study of the Neumann…

Spectral Theory · Mathematics 2015-08-14 Alexander V. Kolesnikov , Emanuel Milman

Employing the inverse function theorem on Banach spaces, we prove that in a $C^{2}(S^{n-1})$-neighborhood of the unit ball, the only solutions of $\Pi^2K=cK$ are origin-centered ellipsoids. Here $K$ is an $n$-dimensional convex body, $\Pi…

Metric Geometry · Mathematics 2018-01-31 Mohammad N. Ivaki

A $\lambda$-convex body in a three-dimensional space form $M^3(c)$ of constant curvature $c$ is a compact convex set $K$ whose boundary $\partial K$ has normal curvatures bounded below by a constant $\lambda>0$ (in a weak sense). Within…

Differential Geometry · Mathematics 2026-03-10 Kostiantyn Drach , Gil Solanes , Kateryna Tatarko

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

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

Hadwiger's covering conjecture is that every $n$-dimensional convex body can be covered by at most $2^n$ of its smaller positive homothetic copies, with $2^n$ copies required only for affine images of $n$-cube. Convex hull of a ball and an…

Metric Geometry · Mathematics 2025-12-16 Andrii Arman , Jaskaran Singh Kaire , Andriy Prymak

We prove the following local version of Blaschke--Kakutani's characterization of ellipsoids: Let $V$ be a finite-dimensional real vector space, $B\subset V$ a convex body with 0 in its interior, and ${2\le k<\dim V}$ an integer. Suppose…

Metric Geometry · Mathematics 2025-04-22 Sergei Ivanov , Daniil Mamaev , Anya Nordskova

This paper is dedicated to study the sine version of polar bodies and establish the $L_p$-sine Blaschke-Santal\'{o} inequality for the $L_p$-sine centroid body. The $L_p$-sine centroid body $\Lambda_p K$ for a star body…

Metric Geometry · Mathematics 2022-06-02 Qingzhong Huang , Ai-Jun Li , Dongmeng Xi , Deping Ye

This paper continues our investigation into the question of when a homotopy $\omega = \{\omega_t\}_{t \in [0,1]}$ of 2-cocycles on a locally compact Hausdorff groupoid $\mathcal{G}$ gives rise to an isomorphism of the $K$-theory groups of…

Operator Algebras · Mathematics 2016-01-20 Elizabeth Gillaspy

The largest volume ratio of given convex body $K \subset \mathbb{R}^n$ is defined as $$\mbox{lvr}(K):= \sup_{L \subset \mathbb{R}^n} \mbox{vr}(K,L),$$ where the $\sup$ runs over all the convex bodies $L$. We prove the following sharp lower…

Metric Geometry · Mathematics 2020-04-21 Daniel Galicer , Mariano Merzbacher , Damián Pinasco

We prove that, for $C^1$-generic diffeomorphisms, if the periodic orbits contained in a homoclinic class $H(p)$ have all their Lyapunov exponents bounded away from 0, then $H(p)$ must be (uniformly) hyperbolic. This is in sprit of the works…

Dynamical Systems · Mathematics 2017-09-27 Xiaodong Wang

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

We will prove the relative homotopy principle for smooth maps with singularities of a given {\cal K}-invariant class with a mild condition. We next study a filtration of the group of homotopy self-equivalences of a given manifold P by…

Geometric Topology · Mathematics 2007-05-23 Yoshifumi Ando

Let K be a d-dimensional convex body, and let $K^{(n)}$ be the intersection of n halfspaces containing $K$ whose bounding hyperplanes are independent and identically distributed. Under suitable distributional assumptions, we prove an…

Metric Geometry · Mathematics 2014-10-15 Károly J. Böröczky , Ferenc Fodor , Daniel Hug

Let G be a compact connected Lie group, and (M,\omega) a Hamiltonian G-space with proper moment map \mu. We give a surjectivity result which expresses the K-theory of the symplectic quotient M//G in terms of the equivariant K-theory of the…

Symplectic Geometry · Mathematics 2007-05-23 Megumi Harada , Gregory D. Landweber