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Moser asked whether the collection of rectangles of dimensions 1 x 1/2, 1/2 x 1/3, 1/3 x 1/4, ..., whose total area equals 1, can be packed into the unit square without overlap, and whether the collection of squares of side lengths 1/2,…

Metric Geometry · Mathematics 2007-05-23 Greg Martin

A rectifier network is a directed acyclic graph with distinguished sources and sinks; it is said to compute a Boolean matrix $M$ that has a $1$ in the entry $(i,j)$ iff there is a path from the $j$th source to the $i$th sink. The smallest…

Computational Complexity · Computer Science 2016-05-20 Dmitry Chistikov , Szabolcs Iván , Anna Lubiw , Jeffrey Shallit

It is well-known that an algorithm exists which approximates the NP-complete problem of Set Cover within a factor of ln(n), and it was recently proven that this approximation ratio is optimal unless P = NP. This optimality result is the…

Computational Complexity · Computer Science 2021-11-30 Erika Melder

For sufficiently large $n$, we show that in every configuration of $n$ points chosen inside the unit square there exists a triangle of area less than $n^{-8/7-1/2000}$. This improves upon a result of Koml\'os, Pintz and Szemer\'edi from…

Combinatorics · Mathematics 2023-05-30 Alex Cohen , Cosmin Pohoata , Dmitrii Zakharov

Following the seminal work of Erlebach and van Leeuwen in SODA 2008, we introduce the minimum ply covering problem. Given a set $P$ of points and a set $S$ of geometric objects, both in the plane, our goal is to find a subset $S'$ of $S$…

Computational Geometry · Computer Science 2019-05-03 Therese Biedl , Ahmad Biniaz , Anna Lubiw

Pseudoline arrangements are fundamental objects in discrete and computational geometry, and different works have tackled the problem of improving the known bounds on the number of simple arrangements of $n$ pseudolines over the past…

Computational Geometry · Computer Science 2025-03-10 Justin Dallant

In this paper, we give the first constant approximation algorithm for the lower bounded facility location (LBFL) problem with general lower bounds. Prior to our work, such algorithms were only known for the special case where all facilities…

Data Structures and Algorithms · Computer Science 2018-05-08 Shi Li

We study the strip packing problem, a classical packing problem which generalizes both bin packing and makespan minimization. Here we are given a set of axis-parallel rectangles in the two-dimensional plane and the goal is to pack them in a…

Data Structures and Algorithms · Computer Science 2018-01-24 Waldo Gálvez , Fabrizio Grandoni , Salvatore Ingala , Arindam Khan

Graph Balancing is the problem of orienting the edges of a weighted multigraph so as to minimize the maximum weighted in-degree. Since the introduction of the problem the best algorithm known achieves an approximation ratio of $1.75$ and it…

Data Structures and Algorithms · Computer Science 2018-11-05 Klaus Jansen , Lars Rohwedder

We prove that every set of n points in the plane has at most $(16+5/6)^n$ rectangulations. This improves upon a long-standing bound of Ackerman. Our proof is based on the cross-graph charging-scheme technique.

Combinatorics · Mathematics 2022-07-18 Hannah Ashbach , Kiki Pichini

The goal of this work is to fill a gap in [Yang, SIAM J. Matrix Anal. Appl, 41 (2020), 1797--1825]. In that work, an approximation procedure was proposed for orthogonal low-rank tensor approximation; however, the approximation lower bound…

Optimization and Control · Mathematics 2021-01-01 Yuning Yang

We present a 4-approximation algorithm for the problem of placing a fewest guards on a 1.5D terrain so that every point of the terrain is seen by at least one guard. This improves on the currently best approximation factor of 5. Our method…

Computational Geometry · Computer Science 2008-09-02 K. Elbassioni , D. Matijevic , J. Mestre , D. Severdija

We show that there is no $(1+\eps)$-approximation algorithm for the problem of covering points in the plane by minimum number of fat triangles of similar size (with the minimum angle of the triangles being close to 45 degrees). Here, the…

Computational Geometry · Computer Science 2009-08-18 Sariel Har-Peled

In the \textsc{2-Dimensional Knapsack} problem (2DK) we are given a square knapsack and a collection of $n$ rectangular items with integer sizes and profits. Our goal is to find the most profitable subset of items that can be packed…

Computational Geometry · Computer Science 2021-03-19 Waldo Gálvez , Fabrizio Grandoni , Arindam Khan , Diego Ramírez-Romero , Andreas Wiese

Sphere packings in high dimensions interest mathematicians and physicists and have direct applications in communications theory. Remarkably, no one has been able to provide exponential improvement on a 100-year-old lower bound on the…

Metric Geometry · Mathematics 2007-05-23 S. Torquato , F. H. Stillinger

The random greedy algorithm for constructing a large partial Steiner-Triple-System is defined as follows. Begin with a complete graph on $n$ vertices and proceed to remove the edges of triangles one at a time, where each triangle removed is…

Combinatorics · Mathematics 2012-10-29 Tom Bohman , Alan Frieze , Eyal Lubetzky

We consider a natural generalization of the Partial Vertex Cover problem. Here an instance consists of a graph G = (V,E), a positive cost function c: V-> Z^{+}, a partition $P_1,..., P_r$ of the edge set $E$, and a parameter $k_i$ for each…

Data Structures and Algorithms · Computer Science 2015-03-19 Suman Kalyan Bera , Shalmoli Gupta , Amit Kumar , Sambuddha Roy

We combine geometric methods with numerical box search algorithm to show that the minimal area of a convex set on the plane which can cover every closed plane curve of unit length is at least 0.0975. This improves the best previous lower…

Metric Geometry · Mathematics 2019-05-02 Bogdan Grechuk , Sittichoke Som-Am

Given a set ${\cal R}=\{R_1,R_2,..., R_n\}$ of $n$ randomly positioned axis parallel rectangles in 2D, the problem of computing the minimum clique cover (MCC) and maximum independent set (MIS) for the intersection graph $G({\cal R})$ of the…

Computational Geometry · Computer Science 2012-12-05 Ritankar Mandal , Anirban Ghosh , Sasanka Roy , Subhas C. Nandy

We show tight lower bounds for the entire trade-off between space and query time for the Approximate Near Neighbor search problem. Our lower bounds hold in a restricted model of computation, which captures all hashing-based approaches. In…

Data Structures and Algorithms · Computer Science 2016-08-22 Alexandr Andoni , Thijs Laarhoven , Ilya Razenshteyn , Erik Waingarten
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