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Rigid graphs have only finitely many realizations. In the recent years significant progress was made in computing the number of such realizations. With this progress it was also possible for the first time to do computations on large sets…

Combinatorics · Mathematics 2025-02-10 Georg Grasegger

A minimally rigid graph, also called Laman graph, models a planar framework which is rigid for a general choice of distances between its vertices. In other words, there are finitely many ways, up to isometries, to realize such a graph in…

Computational Geometry · Computer Science 2022-01-04 Christoph Koutschan

Rigidity theory studies the properties of graphs that can have rigid embeddings in a euclidean space $\mathbb{R}^d$ or on a sphere and which in addition satisfy certain edge length constraints. One of the major open problems in this field…

Algebraic Geometry · Mathematics 2021-02-05 Evangelos Bartzos , Ioannis Z. Emiris , Jan Legerský , Elias Tsigaridas

The number of embeddings of minimally rigid graphs in $\mathbb{R}^D$ is (by definition) finite, modulo rigid transformations, for every generic choice of edge lengths. Even though various approaches have been proposed to compute it, the gap…

Algebraic Geometry · Mathematics 2020-01-24 Evangelos Bartzos , Ioannis Emiris , Jan Legerský , Elias Tsigaridas

A graph is called (generically) rigid in R^d if, for any choice of sufficiently generic edge lengths, it can be embedded in R^d in a finite number of distinct ways, modulo rigid transformations. Here, we deal with the problem of determining…

Computational Geometry · Computer Science 2014-10-24 Stylianos C. Despotakis , Ioannis Z. Emiris

By definition, a rigid graph in $\mathbb{R}^d$ (or on a sphere) has a finite number of embeddings up to rigid motions for a given set of edge length constraints. These embeddings are related to the real solutions of an algebraic system.…

Combinatorics · Mathematics 2021-10-26 Evangelos Bartzos , Ioannis Z. Emiris , Raimundas Vidunas

For minimally rigid graphs, the same edge-length data can admit multiple realizations (up to translations and rotations). Finding graphs with exceptionally many realizations is an extremal problem in rigidity theory, but exhaustive search…

Machine Learning · Computer Science 2026-05-13 Oleksandr Slyvka , Jan Rubeš , Rodrigo Alves , Jan Legerský

We prove new lower and upper bounds on the higher gonalities of finite graphs. These bounds are generalizations of known upper and lower bounds for first gonality to higher gonalities, including upper bounds on gonality involving…

We introduce a recursive procedure for computing the number of realizations of a minimally rigid graph on the sphere up to rotations. We accomplish this by combining two ingredients. The first is a framework that allows us to think of such…

Combinatorics · Mathematics 2023-08-30 Matteo Gallet , Georg Grasegger , Niels Lubbes , Josef Schicho

The diameter of a graph is among its most basic parameters. Since a few years, it moreover became a key issue to compute it for massive graphs in the context of complex network analysis. However, known algorithms, including the ones…

Data Structures and Algorithms · Computer Science 2009-09-30 Clemence Magnien , Matthieu Latapy , Michel Habib

A graph is said to be rigid if, given a generic realisation of the graph as a bar-and-joint framework in the plane, there exist only finitely many other realisations of the graph with the same edge lengths modulo rotations, reflections and…

Combinatorics · Mathematics 2025-10-07 Sean Dewar , Georg Grasegger , Josef Schicho , Ayush Kumar Tewari , Audie Warren

In this paper, we investigate three fundamental problems regarding cut complexes of graphs: their realizability, the uniqueness of graph reconstruction from them, and their algorithmic recognition. We define the parameter $m(d,n)$ as the…

Combinatorics · Mathematics 2025-12-16 Yufeng Shen , Zhiyu Song , Fenglin Yu , Leopold Wuhan Zhou , Jingqi Zhuang

We implement and test the performances of several approximation algorithms for computing the minimum dominating set of a graph. These algorithms are the standard greedy algorithm, the recent LP rounding algorithms and a hybrid algorithm…

Data Structures and Algorithms · Computer Science 2020-09-11 Jonathan S. Li , Rohan Potru , Farhad Shahrokhi

Determining the number of (complex) realisations of a rigid graph for a specific choice of edge lengths is a fundamental problem in discrete geometry. In this article we provide two new tools for determining realisation numbers in arbitrary…

Combinatorics · Mathematics 2026-02-25 Sean Dewar , Anthony Nixon , Ben Smith

Research about crossings is typically about minimization. In this paper, we consider \emph{maximizing} the number of crossings over all possible ways to draw a given graph in the plane. Alpert et al. [Electron. J. Combin., 2009] conjectured…

Computational Geometry · Computer Science 2017-05-16 Markus Chimani , Stefan Felsner , Stephen Kobourov , Torsten Ueckerdt , Pavel Valtr , Alexander Wolff

In communication field, an important issue is to group users and base stations to as many as possible subnetworks satisfying certain interference constraints. These problems are usually formulated as a graph partition problems which…

Combinatorics · Mathematics 2020-09-30 Chicheng Ma , Yucong Tang , Guanghui Wang , Guiying Yan , Bo Bai

We establish a strong, geometric lower bound on the (sequential) topological complexity of the unordered configuration spaces of a general graph. As an application, we show that, for most graphs, the topological complexity eventually…

Algebraic Topology · Mathematics 2026-02-05 Ben Knudsen

In any attempt at designing an efficient algorithm for the minimum vertex cover problem, obtaining good upper and lower bounds for the vertex cover number could be crucial. In this article we present a modified greedy algorithm of…

Combinatorics · Mathematics 2019-01-04 R. Dharmarajan , D. Ramachandran

This article provides sharp bounds for the maximum number of edges possible in a simple graph with restricted values of two of the three parameters, namely, maxi- mum matching size, independence number and maximum degree. We also construct…

Combinatorics · Mathematics 2012-03-08 Niraj Khare , Nishali Mehta , Naushad Puliyambalath

We consider the task of drawing a graph on multiple horizontal layers, where each node is assigned a layer, and each edge connects nodes of different layers. Known algorithms determine the orders of nodes on each layer to minimize crossings…

Data Structures and Algorithms · Computer Science 2025-03-03 Alexander Dobler , Jakob Roithinger
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