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We prove that the active-set method needs an exponential number of iterations in the worst-case to maximize a convex quadratic function subject to linear constraints, regardless of the pivot rule used. This substantially improves over the…

Discrete Mathematics · Computer Science 2025-10-23 Eleon Bach , Yann Disser , Sophie Huiberts , Nils Mosis

We study the topology of the set X of the solutions of a system of two quadratic inequalities in the real projective space RP^n (e.g. X is the intersection of two real quadrics). We give explicit formulae for its Betti numbers and for those…

Algebraic Geometry · Mathematics 2012-09-07 Antonio Lerario

This article describes a method to compute successive convex approximations of the convex hull of a set of points in R^n that are the solutions to a system of polynomial equations over the reals. The method relies on sums of squares of…

Optimization and Control · Mathematics 2010-07-27 João Gouveia , Rekha R. Thomas

We consider consecutive random subdivision of polygons described as follows. Given an initial convex polygon with $d\ge 3$ edges, we choose a point at random on each edge, such that the proportions in which these points divide edges are…

Probability · Mathematics 2017-08-23 Nguyen Tuan Minh , Stanislav Volkov

The simplest way to generate a lattice of convex sets is to consider an initial set of points and draw segments, triangles, and any convex hull from it, then intersect them to obtain new points, and so forth. The result is an infinite…

Combinatorics · Mathematics 2024-07-25 Carles Cardó

We show the effectiveness of automatic differentiation in efficiently and correctly computing and controlling the spectrum of implicitly linear operators, a rich family of layer types including all standard convolutional and dense layers.…

Machine Learning · Computer Science 2024-10-08 Ali Ebrahimpour Boroojeny , Matus Telgarsky , Hari Sundaram

A convex polygon $A$ is related to a convex $m$-gon $K= \bigcap_{i=1}^m k_i^+$, where $k_1^+,..., k_m^+$ are the $m$ halfplanes whose intersection is equal to $K$, if $A$ is the intersection of halfplanes $a_1^+,...,a_l$, each of which is a…

Metric Geometry · Mathematics 2012-01-05 Meir Katchalski , David Nashtir

For a finite set $A\subset \mathbb{R}^d$, let $\Delta(A)$ denote the spread of $A$, which is the ratio of the maximum pairwise distance to the minimum pairwise distance. For a positive integer $n$, let $\gamma_d(n)$ denote the largest…

Combinatorics · Mathematics 2022-12-20 Adrian Dumitrescu , Csaba D. Tóth

Steinitz's theorem states that if a point $a \in \mathrm{int\,conv\,} X$ for a set $X \subset \mathbb{R}^d$, then $X$ contains a subset $Y$ of size at most $2d$ such that $a \in \mathrm{int\,conv\,}Y$. The bound $2d$ is best possible here.…

Combinatorics · Mathematics 2026-03-13 Imre Bárány , Yun Qi

A point set $P \subset {\Bbb{R}}^d$ is {\it separated} if the minimum distance between any two points in $P$ is at least $1$. For $d \ne 4,5,$ we determine, for every $t_1,t_2 \ge 1$, and for $n$ at least a suitable $n_d$, the maximum…

Metric Geometry · Mathematics 2025-10-07 P. Erdős , E. Makai, , J. Pach

Geometric hitting set problems, in which we seek a smallest set of points that collectively hit a given set of ranges, are ubiquitous in computational geometry. Most often, the set is discrete and is given explicitly. We propose new…

Computational Geometry · Computer Science 2025-04-24 Jean Cardinal , Xavier Goaoc , Sarah Wajsbrot

In 2012 Gubeladze (Adv.\ Math.\ 2012) introduced the notion of k-convex-normal polytopes to show that integral polytopes all of whose edges are longer than 4d(d+1) have the integer decomposition property. In the first part of this paper we…

Combinatorics · Mathematics 2014-10-24 Christian Haase , Jan Hofmann

Let $P$ be a set of $n$ points in the plane. We consider a variation of the classical Erd\H{o}s-Szekeres problem, presenting efficient algorithms with $O(n^3)$ running time and $O(n^2)$ space complexity that compute: (1) A subset $S$ of $P$…

Computational Geometry · Computer Science 2024-12-18 Hernán González-Aguilar , David Orden , Pablo Pérez-Lantero , David Rappaport , Carlos Seara , Javier Tejel , Jorge Urrutia

We consider the convex hull of the perturbed point process comprised of $n$ i.i.d. points, each distributed as the sum of a uniform point on the unit sphere $\S^{d-1}$ and a uniform point in the $d$-dimensional ball centered at the origin…

Probability · Mathematics 2019-12-24 Pierre Calka , J. E. Yukich

We consider the convex hull of a finite sample of i.i.d. points uniformly distributed in a convex body in $\R^d$, $d\geq 2$. We prove an exponential deviation inequality, which leads to rate optimal upper bounds on all the moments of the…

Statistics Theory · Mathematics 2013-11-13 Victor-Emmanuel Brunel

Motivated by a question of Galby, Munaro, and Yang (SoCG 2023) asking whether every graph class of bounded layered tree-independence number admits clique-based separators of sublinear weight, we investigate relations between layered…

Combinatorics · Mathematics 2025-06-17 Clément Dallard , Martin Milanič , Andrea Munaro , Shizhou Yang

Consider a set $P \subseteq \Re^d$ of $n$ points, and a convex body $C$ provided via a separation oracle. The task at hand is to decide for each point of $P$ if it is in $C$ using the fewest number of oracle queries. We show that one can…

Computational Geometry · Computer Science 2021-04-02 Sariel Har-Peled , Mitchell Jones , Saladi Rahul

A balanced partition is a clustering of a graph into a given number of equal-sized parts. For instance, the Bisection problem asks to remove at most k edges in order to partition the vertices into two equal-sized parts. We prove that…

Discrete Mathematics · Computer Science 2016-01-12 René van Bevern , Andreas Emil Feldmann , Manuel Sorge , Ondřej Suchý

Linek's 1989 problem asks whether the numbers of independent sets of trees avoid infinitely many positive integers. We show that the set of natural numbers realized as the number of independent sets of a tree has a lower growth exponent of…

Combinatorics · Mathematics 2026-04-22 Swee Hong Chan , Steven Heilman , Greta Panova

In $d$-Scattered Set we are given an (edge-weighted) graph and are asked to select at least $k$ vertices, so that the distance between any pair is at least $d$, thus generalizing Independent Set. We provide upper and lower bounds on the…

Computational Complexity · Computer Science 2018-11-13 Ioannis Katsikarelis , Michael Lampis , Vangelis Th. Paschos