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The Levy-Gromov inequality states that round spheres have the least isoperimetric profile (normalized by total volume) among Riemannian manifolds with a fixed positive lower bound on the Ricci tensor. In this note we study critical metrics…

Differential Geometry · Mathematics 2020-04-22 Fabio Cavalletti , Francesco Maggi , Andrea Mondino

In this paper we solve several reverse isoperimetric problems in the class of $\lambda$-convex bodies, i.e., convex bodies whose curvature at each point of their boundary is bounded below by some $\lambda > 0$. We give an affirmative answer…

Metric Geometry · Mathematics 2023-03-07 Kostiantyn Drach , Kateryna Tatarko

Recall that the radius of a compact metric space $(X, dist)$ is given by $rad\ X = \min_{x\in X} \max_{y\in X} dist(x,y)$. In this paper we generalize Berger's $\frac{1}{4}$-pinched rigidity theorem and show that a closed, simply connected,…

dg-ga · Mathematics 2008-02-03 Frederick Wilhelm

We present a short proof of the Alexandrov-Fenchel inequalities for mixed volumes of convex bodies.

Metric Geometry · Mathematics 2019-06-25 D. Cordero-Erausquin , B. Klartag , Q. Merigot , F. Santambrogio

In this article we introduce a notion of normalized angle for Lorentzian pre-length spaces. This concept allows us to prove some equivalences to the definition of timelike curvature bounds from below for Lorentzian pre-length spaces.…

Differential Geometry · Mathematics 2022-09-28 Waldemar Barrera , Luis Montes de Oca , Didier A. Solis

Extending the celebrated results of Alexandrov (1958) and Korevaar-Ros (1988) for smooth sets, as well as the results of Schneider (1979) and the first author (1999) for arbitrary convex bodies, we obtain for the first time the…

Metric Geometry · Mathematics 2022-11-21 Daniel Hug , Mario Santilli

In this paper we introduce a family of examples that can be regarded as spaces of nonpositive curvature, but with the distinct quality that they are not complete as metric spaces. This amounts to the fact that they are modelled on a finite…

Metric Geometry · Mathematics 2009-08-27 Cristian Conde , Gabriel Larotonda

We demonstrate that the property of being Alexandrov immersed is preserved along mean curvature flow. Furthermore, we demonstrate that mean curvature flow techniques for mean convex embedded flows such as noncollapsing and gradient…

Differential Geometry · Mathematics 2022-06-29 Ben Lambert , Elena Mäder-Baumdicker

We prove a collection of reverse Alexandrov-Fenchel type inequalities in anisotropic, Euclidean, spherical, and hyperbolic settings. The unifying principle is that the relevant deficit is controlled by curvature radius data, or equivalently…

Differential Geometry · Mathematics 2026-05-06 Kwok-kun Kwong , Scott Parkins , Glen Wheeler

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

For appropriately values of $H$, we obtain an area estimate for a complete non-compact $H$-surface of finite topology and finite area, embedded in a three-manifold of negative curvature. Moreover, in the case of equality and under…

Differential Geometry · Mathematics 2017-06-29 Vanderson Lima

We give a metric characterization of the scalar curvature of a smooth Riemannian manifold, analyzing the maximal distance between $(n+1)$ points in infinitesimally small neighborhoods of a point. Since this characterization is purely in…

Differential Geometry · Mathematics 2022-12-19 Giona Veronelli

The Alexandrov-Fenchel inequality, a far-reaching generalization of the classical isoperimetric inequality to arbitrary mixed volumes, lies at the heart of convex geometry. The characterization of its extremal bodies is a long-standing open…

Metric Geometry · Mathematics 2022-02-04 Yair Shenfeld , Ramon van Handel

We show that closed manifolds supporting a nonpositively curved metric with negative $([\frac{n}{4}]+1)$-Ricci curvature, have positive simplicial volume. This answers a special case of a conjecture of Gromov.

Differential Geometry · Mathematics 2020-07-24 Chris Connell , Shi Wang

Let a compact Lie group act isometrically on a non-collapsing sequence of compact Alexandrov spaces with fixed dimension and uniform lower curvature and upper diameter bounds. If the sequence of actions is equicontinuous and converges in…

Differential Geometry · Mathematics 2020-01-23 John Harvey

We prove a sharp isoperimetric inequality for measured Finsler manifolds having non-negative Ricci curvature and Euclidean volume growth. We also prove a rigidity result for this inequality, under the additional hypotheses of boundedness of…

Differential Geometry · Mathematics 2024-06-05 Davide Manini

We consider mean-convex Alexandrov embedded surfaces in the round unit 3-sphere, and show under which conditions it is possible to continuously deform these preserving mean-convex Alexandrov embeddedness.

Differential Geometry · Mathematics 2015-08-21 Laurent Hauswirth , Martin Kilian , Martin Ulrich Schmidt

We study all the ways that a given convex body in $d$ dimensions can break into countably many pieces that move away from each other rigidly at constant velocity, with no rotation or shearing. The initial velocity field is locally constant,…

Analysis of PDEs · Mathematics 2025-09-24 Jian-Guo Liu , Robert L. Pego

We develop and analyze a variant of Nesterov's accelerated gradient descent (AGD) for minimization of smooth non-convex functions. We prove that one of two cases occurs: either our AGD variant converges quickly, as if the function was…

Optimization and Control · Mathematics 2017-05-09 Yair Carmon , Oliver Hinder , John C. Duchi , Aaron Sidford

We prove that sufficiently collapsed, closed and irreducible three-dimensional Alexandrov spaces are modeled on one of the eight three-dimensional Thurston geometries. This extends a result of Shioya and Yamaguchi, originally formulated for…

Differential Geometry · Mathematics 2020-05-21 Fernando Galaz-Garcia , Luis Guijarro , Jesús Núñez-Zimbrón