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We introduce and study a new class of $\eps$-convex bodies (extending the class of convex bodies) in metric and normed linear spaces. We analyze relations between characteristic properties of convex bodies, demonstrate how $\eps$-convex…

Differential Geometry · Mathematics 2016-02-03 Vladimir Golubyatnikov , Vladimir Rovenski

We prove the following sparse approximation result for polytopes. Assume that $Q$ is a polytope in John's position. Then there exist at most $2d$ vertices of $Q$ whose convex hull $Q'$ satisfies $Q \subseteq - 2d^2 \, Q'$. As a consequence,…

Metric Geometry · Mathematics 2022-09-13 Víctor Hugo Almendra-Hernández , Gergely Ambrus , Matthew Kendall

In this paper, we introduce a generalized notion of monotone property and prove some results regarding existence and uniqueness of multi-tupled fixed points for nonlinear contraction mappings satisfying monotone property in ordered complete…

Functional Analysis · Mathematics 2016-10-04 Aftab Alam , Mohammad Imdad , Stojan Radenovic

We propose a combinatorial framework to analyze quantitative Helly-type questions. Using this framework, we prove a Quantitative Fractional Helly Theorem with Fractional Helly Number 3d and a stability version of the Quantitative Helly…

Combinatorics · Mathematics 2023-04-10 Attila Jung

Helly's theorem is a classical result concerning the intersection patterns of convex sets in $\mathbb{R}^d$. Two important generalizations are the colorful version and the fractional version. Recently, B\'{a}r\'{a}ny et al. combined the…

Combinatorics · Mathematics 2019-07-04 Minki Kim

In the setting of step two Carnot groups, we show a "cone property" for horizontally convex sets. Namely we prove that, given a horizontally convex set $C$, a pair of points $P\in \partial C$ and $Q\in $ int $C$, both belonging to a…

Metric Geometry · Mathematics 2019-02-26 Daniele Morbidelli

We introduce a new variant of quantitative Helly-type theorems: the minimal \emph{"homothetic distance"} of the intersection of a family of convex sets to the intersection of a subfamily of a fixed size. As an application, we establish the…

Metric Geometry · Mathematics 2021-11-03 Grigory Ivanov , Márton Naszódi

We establish a monotonicity-type property of volume of central hyperplane sections of the 1-symmetric convex bodies, with applications to chessboard cutting. We parallel this for projections with a new convexity-type property for Rademacher…

Metric Geometry · Mathematics 2026-03-05 Joseph Kalarickal , David Rotunno , Salil Singh , Tomasz Tkocz

Brazitikos' results on quantititative Helly-type theorems (for the volume and for the diameter) rely on the work of Srivastava on sparsification of John's decompositions. We change this technique by a stronger recent result due to Friedland…

Metric Geometry · Mathematics 2021-03-03 Tomás Fernandez Vidal , Daniel Galicer , Mariano Merzbacher

This survey presents recent Helly-type geometric theorems published since the appearance of the last comprehensive survey, more than ten years ago. We discuss how such theorems continue to be influential in computational geometry and in…

Metric Geometry · Mathematics 2016-08-22 Nina Amenta , Jesús A. De Loera , Pablo Soberón

We prove variations of Carath\'eodory's, Helly's and Tverberg's theorems where the sets involved are measured according to continuous functions such as the volume or diameter. Among our results, we present continuous quantitative versions…

Metric Geometry · Mathematics 2016-03-21 J. A. De Loera , R. N. La Haye , D. Rolnick , P. Soberón

We use symplectic techniques to obtain partial results on Mahler's conjecture about the product of the volume of a convex body and the volume of its polar. We confirm the conjecture for hyperplane sections or projections of $\ell_p$-balls…

Metric Geometry · Mathematics 2022-02-03 Roman Karasev

For convex partitions of a convex body $B$ we prove that we can put a homothetic copy of $B$ into each set of the partition so that the sum of homothety coefficients is $\ge 1$. In the plane the partition may be arbitrary, while in higher…

Combinatorics · Mathematics 2012-12-27 Arseniy Akopyan , Roman Karasev

We introduce new classes of general monotone sequences and study their properties. For functions whose Fourier coefficients belong to these classes, we establish Hardy-Littlewood-type theorems.

Classical Analysis and ODEs · Mathematics 2025-10-17 Askhat Mukanov , Erlan Nursultanov

We prove that, among weighted isotropic perimeters, only constant multiples of the Euclidean perimeter satisfy the monotonicity property on nested convex bodies. Although the analogous result fails for general weighted anisotropic…

Metric Geometry · Mathematics 2024-04-09 Giorgio Saracco , Giorgio Stefani

Qualitatively, a no-dimensional Helly-type theorem says that if every small subfamily of convex sets has a common point in a bounded region, then suitable neighborhoods of all the sets in the whole family have a common point. Quantitative…

Functional Analysis · Mathematics 2026-03-27 Grigory Ivanov

Short and transparent proofs of central limit theorems for intrinsic volumes of random polytopes in smooth convex bodies are presented. They combine different tools such as estimates for floating bodies with Stein's method from probability…

Metric Geometry · Mathematics 2017-11-06 Christoph Thaele , Nicola Turchi , Florian Wespi

This paper presents sixteen quantitative versions of the classic Tverberg, Helly, & Caratheodory theorems in combinatorial convexity. Our results include measurable or enumerable information in the hypothesis and the conclusion. Typical…

Metric Geometry · Mathematics 2015-04-03 J. A. De Loera , R. N. La Haye , D. Rolnick , P. Soberón

In this short note we show that Helly's Intersection Theorem holds for convex sets in uniquely geodesic spaces (in particular in CAT(0) spaces) without the assumption that the convex sets are open or closed.

Metric Geometry · Mathematics 2014-05-20 Sergei Ivanov

We consider some questions concerning the monotonicity properties of entropy and mean entropy of states on translationally invariant systems (classical lattice, quantum lattice and quantum continuous). By taking the property of strong…

Mathematical Physics · Physics 2008-11-26 Amanda R. Kay , Bernard S. Kay