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A transitive graph is 2-dimensional if it can be represented as the intersection of two linear orders. Such representations make answering of reachability queries trivial, and allow many problems that are NP-hard on arbitrary graphs to be…

Discrete Mathematics · Computer Science 2019-04-09 Henning Koehler

In this paper, a theorem about similar triangles is proved. It shows that two small and four large triangles similar to the original triangle can appear if we choose well among several intersections of the perpendicular bisectors of the…

General Mathematics · Mathematics 2023-11-14 Hiroki Naka , Takahiko Fujita , Naohiro Yoshida

Graphs are a basic tool for the representation of modern data. The richness of the topological information contained in a graph goes far beyond its mere interpretation as a one-dimensional simplicial complex. We show how topological…

Combinatorics · Mathematics 2018-10-11 Mattia G. Bergomi , Massimo Ferri , Lorenzo Zuffi

In the Segment Intersection Graph Representation Problem, we want to represent the vertices of a graph as straight line segments in the plane such that two segments cross if and only if there is an edge between the corresponding vertices.…

Computational Geometry · Computer Science 2025-02-25 Simon D. Fink , Matthias Pfretzschner , Peter Stumpf

We consider the problem of assigning appearing times to the edges of a digraph in order to maximize the (average) temporal reachability between pairs of nodes. Motivated by the application to public transit networks, where edges cannot be…

Discrete Mathematics · Computer Science 2025-01-22 Filippo Brunelli , Pierluigi Crescenzi , Laurent Viennot

We prove that the following problem is complete for the existential theory of the reals: Given a planar graph and a polygonal region, with some vertices of the graph assigned to points on the boundary of the region, place the remaining…

Computational Complexity · Computer Science 2018-09-07 Anna Lubiw , Tillmann Miltzow , Debajyoti Mondal

We initiate the study of diameter computation in geometric intersection graphs from the fine-grained complexity perspective. A geometric intersection graph is a graph whose vertices correspond to some shapes in $d$-dimensional Euclidean…

Computational Geometry · Computer Science 2022-03-11 Karl Bringmann , Sándor Kisfaludi-Bak , Marvin Künnemann , André Nusser , Zahra Parsaeian

A paradigm that was successfully applied in the study of both pure and algorithmic problems in graph theory can be colloquially summarized as stating that "any graph is close to being the disjoint union of expanders". Our goal in this paper…

Combinatorics · Mathematics 2015-02-03 Guy Moshkovitz , Asaf Shapira

Let $G$ be a tripartite graph with $N$ vertices in each vertex class. If each vertex is adjacent to at least $(2/3)N$ vertices in each of the other classes, then either $G$ contains a subgraph that consists of $N$ vertex-disjoint triangles…

Combinatorics · Mathematics 2016-05-24 Csaba Magyar , Ryan R. Martin

Modern graph or network datasets often contain rich structure that goes beyond simple pairwise connections between nodes. This calls for complex representations that can capture, for instance, edges of different types as well as so-called…

Social and Information Networks · Computer Science 2020-02-19 Ilya Amburg , Nate Veldt , Austin R. Benson

Let G = (V,E) be an n-vertex graph and M_d a d-vertex graph, for some constant d. Is M_d a subgraph of G? We consider this problem in a model where all n processes are connected to all other processes, and each message contains up to O(log…

Distributed, Parallel, and Cluster Computing · Computer Science 2012-11-06 Danny Dolev , Christoph Lenzen , Shir Peled

Graph drawings are useful tools for exploring the structure and dynamics of data that can be represented by pair-wise relationships among a set of objects. Typical real-world social, biological or technological networks exhibit high…

Social and Information Networks · Computer Science 2018-07-05 Christian Schulz

Graphs are used in almost every scientific discipline to express relations among a set of objects. Algorithms that compare graphs, and output a closeness score, or a correspondence among their nodes, are thus extremely important. Despite…

Discrete Mathematics · Computer Science 2020-11-17 Sam Safavi , José Bento

Geometric modeling by constraints, whose applications are of interest to communities from various fields such as mechanical engineering, computer aided design, symbolic computation or molecular chemistry, is now integrated into standard…

Computational Geometry · Computer Science 2018-03-06 Samy Ait-Aoudia , Adel Moussaoui , Khaled Abid , Dominique Michelucci

Disk contact representations realize graphs by mapping vertices bijectively to interior-disjoint disks in the plane such that two disks touch each other if and only if the corresponding vertices are adjacent in the graph. Deciding whether a…

Computational Geometry · Computer Science 2015-09-03 Boris Klemz , Martin Nöllenburg , Roman Prutkin

In this paper we consider the separability problem for bipartite quantum states arising from graphs. Earlier it was proved that the degree criterion is the graph-theoretic counterpart of the familiar positive partial transpose criterion for…

Quantum Physics · Physics 2016-07-29 Supriyo Dutta , Bibhas Adhikari , Subhashish Banerjee , R. Srikanth

Graphings are special bounded-degree graphs on probability spaces, representing limits of graph sequences that are convergent in a local or local-global sense. We describe a procedure for turning the underlying space into a compact metric…

Combinatorics · Mathematics 2021-02-17 László Lovász

Polygons are cycles embedded into the plane; their vertices are associated with $x$- and $y$-coordinates and the edges are straight lines. Here, we consider a set of polygons with pairwise non-overlapping interior that may touch along their…

Computational Geometry · Computer Science 2024-09-23 Carsten R. Seemann , Peter F. Stadler , Marc Hellmuth

We associate to triangulations of infinite type surface a type of flip graph where simultaneous flips are allowed. Our main focus is on understanding exactly when two triangulations can be related by a sequence of flips. A consequence of…

Geometric Topology · Mathematics 2020-11-05 Ariadna Fossas , Hugo Parlier

Real-world graphs often manifest as a massive temporal stream of edges. The need for real-time analysis of such large graph streams has led to progress on low memory, one-pass streaming graph algorithms. These algorithms were designed for…

Data Structures and Algorithms · Computer Science 2014-10-16 Madhav Jha , C. Seshadhri , Ali Pinar