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Related papers: Tverberg-type theorems for intersecting by rays

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We give a natural sufficient condition for an intersection graph of compact convex sets in R^d to have a balanced separator of sublinear size. This condition generalizes several previous results on sublinear separators in intersection…

Combinatorics · Mathematics 2020-01-07 Zdenek Dvorak , Rose McCarty , Sergey Norin

We explore the applications of Lorentzian polynomials to the fields of algebraic geometry, analytic geometry and convex geometry. In particular, we establish a series of intersection theoretic inequalities, which we call rKT property, with…

Algebraic Geometry · Mathematics 2024-05-24 Jiajun Hu , Jian Xiao

Consider a collection of vector subspaces of a given vector space and a collection of projectors on these vector spaces, can we decompose the vector space into a product of vector subspaces such that the projectors are isomorphic to…

Category Theory · Mathematics 2021-05-25 Grégoire Sergeant-Perthuis

This is a revision of some expository lecture notes written originally for a 5-hour minicourse on the intersection theory of punctured holomorphic curves and its applications in 3-dimensional contact topology. The main lectures are aimed…

Symplectic Geometry · Mathematics 2019-08-19 Chris Wendl

We study intersections of orbits in polynomial semigroup dynamics with lines on the affine plane over a number field, extending previous work of D. Ghioca, T. Tucker, M. Zieve (2008)

Number Theory · Mathematics 2021-07-01 Jorge Mello

We prove that a typical compact set does not contain any similar copy of a given pattern. We also prove that a typical compact set of $[0,1]^{d} (d\geq 2)$ intersects any $(d-1)$-dimensional plane in at most $d$ points. We study the…

Classical Analysis and ODEs · Mathematics 2015-12-16 Changhao Chen

Popov classified crystallographic complex reflection groups by determining lattices they stabilize. These analogs of affine Weyl groups have infinite order and are generated by reflections about affine hyperplanes; most arise as the…

Combinatorics · Mathematics 2020-04-21 Philip Puente , Anne V. Shepler

We give a short new proof of a version of the Kruskal-Katona theorem due to Lov\'asz. Our method can be extended to a stability result, describing the approximate structure of configurations that are close to being extremal, which answers a…

Combinatorics · Mathematics 2008-06-13 Peter Keevash

In this paper, we generalize Minkowski's theorem. This theorem is usually stated for a centrally symmetric convex body and a lattice both included in $\mathbb{R}^n$. In some situations, one may replace the lattice by a more general set for…

Metric Geometry · Mathematics 2016-04-15 Pierre-Antoine Guihéneuf , Emilien Joly

We say that a set $A$ \emph{$t$-intersects} a set $B$ if $A$ and $B$ have at least $t$ common elements. Two families $\mathcal{A}$ and $\mathcal{B}$ are said to be \emph{cross-$t$-intersecting} if each set in $\mathcal{A}$ $t$-intersects…

Combinatorics · Mathematics 2013-12-12 Peter Borg

The celebrated theorem of Ahlswede and Khachatrian determines the maximum size of a family of $k$-element subsets of an $n$-element set where the intersection of any two subsets has at least $r$ elements. This survey first gives a…

Combinatorics · Mathematics 2016-02-09 Gyula O. H. Katona

Many star bodies have convex subsets with approximately the same Gaussian measure (of the complement). Inspired by this phenomenon, and in connection with the randomized Dvoretzky theorem for Lorentz spaces, we derive bounds on the…

Functional Analysis · Mathematics 2022-06-22 Daniel J. Fresen

We consider the intersections of fractal k-cubes of order n and intersections of their respective opposite l-faces. The main result of the paper is the theorem on representation of such intersection as the attractor of a graph-directed…

Metric Geometry · Mathematics 2024-10-07 Andrei Tetenov , Dmitry Drozdov

A tropical version of the Schauder fixed point theorem for compact subsets of tropical linear spaces is proved.

Functional Analysis · Mathematics 2009-09-17 G. B. Shpiz , G. L. Litvinov

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

This paper deals with the theory of collisions between two ultracold particles with a special focus on molecules. It describes the general features of the scattering theory of two particles with internal structure, using a time-independent…

Atomic Physics · Physics 2017-03-28 Goulven Quéméner

We discuss various phenomena of tangency in projective and convex geometry.

Algebraic Geometry · Mathematics 2011-03-07 Roland Abuaf

Let A be a commutative noetherian local DG-ring with bounded cohomology. The Intersection Theorem for DG-modules is examined and some of its applications are provided. The first is to prove the DG-setting of the amplitude inequality, New…

Commutative Algebra · Mathematics 2024-05-02 Xiaoyan Yang

Let $P_1, P_2,\ldots, P_{d+1}$ be pairwise disjoint $n$-element point sets in general position in $d$-space. It is shown that there exist a point $O$ and suitable subsets $Q_i\subseteq P_i \; (i=1, 2, \ldots, d+1)$ such that $|Q_i|\geq…

Combinatorics · Mathematics 2016-09-06 János Pach

Rays are classes of an equivalence relation on a module V over a supertropical semiring. They provide a version of convex geometry, supported by a "supertropical trigonometry" and compatible with quasilinearity, in which the CS-ratio takes…

Rings and Algebras · Mathematics 2019-10-01 Zur Izhakian , Manfred Knebusch