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Visibility graph of a simple polygon is a graph with the same vertex set in which there is an edge between a pair of vertices if and only if the segment through them lies completely inside the polygon. Each pair of adjacent vertices on the…

Computational Geometry · Computer Science 2020-02-18 Hossein Boomari Soheila Farokhi

In the area of beyond-planar graphs, i.e. graphs that can be drawn with some local restrictions on the edge crossings, the recognition problem is prominent next to the density question for the different graph classes. For 1-planar graphs,…

Data Structures and Algorithms · Computer Science 2021-08-04 Henry Förster , Michael Kaufmann , Chrysanthi N. Raftopoulou

We define a natural class of graphs by generalizing prior notions of visibility, allowing the representing regions and sightlines to be arbitrary. We consider mainly the case of compact connected representing regions, proving two results…

Combinatorics · Mathematics 2007-05-23 Mike Develin , Stephen Hartke , David Petrie Moulton

We analyse properties of geometric intersection graphs to show the strict containment between some natural classes of geometric intersection graphs. In particular, we show the following properties: - A graph $G$ is outerplanar if and only…

Combinatorics · Mathematics 2017-02-02 Sergio Cabello , Miha Jejčič

We give an algorithm to morph planar graph drawings that achieves small grid size at the expense of allowing a constant number of bends on each edge. The input is an $n$-vertex planar graph and two planar straight-line drawings of the graph…

Computational Geometry · Computer Science 2024-09-09 Therese Biedl , Anna Lubiw , Jack Spalding-Jamieson

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

Vertex connectivity and edge connectivity are fundamental concepts in graph theory that have been widely studied from both structural and algorithmic perspectives. The focus of this paper is on computing these two parameters for graphs…

Data Structures and Algorithms · Computer Science 2025-10-14 Therese Biedl , Prosenjit Bose , Karthik Murali

An obstacle representation of a plane graph G is V(G) together with a set of opaque polygonal obstacles such that G is the visibility graph on V(G) determined by the obstacles. We investigate the problem of computing an obstacle…

Computational Geometry · Computer Science 2011-08-15 Matthew P. Johnson , Deniz Sarioz

A topological drawing of a graph is fan-planar if for each edge $e$ the edges crossing $e$ form a star and no endpoint of $e$ is enclosed by $e$ and its crossing edges. A fan-planar graph is a graph admitting such a drawing. Equivalently,…

Discrete Mathematics · Computer Science 2021-07-16 Michael Kaufmann , Torsten Ueckerdt

Untangling is a process in which some vertices of a planar graph are moved to obtain a straight-line plane drawing. The aim is to move as few vertices as possible. We present an algorithm that untangles the cycle graph C_n while keeping at…

Computational Geometry · Computer Science 2011-02-07 Josef Cibulka

Given a planar graph $G$, we consider drawings of $G$ in the plane where edges are represented by straight line segments (which possibly intersect). Such a drawing is specified by an injective embedding $\pi$ of the vertex set of $G$ into…

Discrete Mathematics · Computer Science 2011-05-20 Mihyun Kang , Oleg Pikhurko , Alexander Ravsky , Mathias Schacht , Oleg Verbitsky

We show that every graph of maximum degree 3 can be represented as the intersection graph of axis parallel boxes in three dimensions, that is, every vertex can be mapped to an axis parallel box such that two boxes intersect if and only if…

Combinatorics · Mathematics 2011-08-30 Abhijin Adiga , L. Sunil Chandran

A plus-contact representation of a planar graph $G$ is called $c$-balanced if for every plus shape $+_v$, the number of other plus shapes incident to each arm of $+_v$ is at most $ c \Delta +O(1)$, where $\Delta$ is the maximum degree of…

Computational Geometry · Computer Science 2017-09-01 Therese Biedl , Debajyoti Mondal

Bipartite graphs model the relationship between two disjoint sets of objects. They have a wide range of applications and are often visualized as a 2-layered drawing, where each set of objects is visualized as a set of vertices (points) on…

Computational Geometry · Computer Science 2022-08-30 Reyan Ahmed , Stephen Kobourov , Myroslav Kryven

It is proved that every series-parallel digraph whose maximum vertex-degree is $\Delta$ admits an upward planar drawing with at most one bend per edge such that each edge segment has one of $\Delta$ distinct slopes. This is shown to be…

Computational Geometry · Computer Science 2016-08-31 Emilio Di Giacomo , Giuseppe Liotta , Fabrizio Montecchiani

We consider the problem of morphing between contact representations of a plane graph. In an $\mathcal F$-contact representation of a plane graph $G$, vertices are realized by internally disjoint elements from a family $\mathcal F$ of…

Computational Geometry · Computer Science 2019-03-19 Patrizio Angelini , Steven Chaplick , Sabine Cornelsen , Giordano Da Lozzo , Vincenzo Roselli

An \emph{obstacle representation} of a graph $G$ is a straight-line drawing of $G$ in the plane together with a collection of connected subsets of the plane, called \emph{obstacles}, that block all non-edges of $G$ while not blocking any of…

A geometric graph is a drawing of a graph in the plane where the vertices are drawn as points in general position and the edges as straight-line segments connecting their endpoints. It is plane if it contains no crossing edges. We study…

Computational Geometry · Computer Science 2025-06-26 Marco Ricci , Jonathan Rollin , André Schulz , Alexandra Weinberger

A plane graph is called a rectangular graph if each of its edges can be oriented either horizontally or vertically, each of its interior regions is a four-sided region and all interior regions can be fitted in a rectangular enclosure. If…

Combinatorics · Mathematics 2021-01-19 Vinod Kumar , Krishnendra Shekhawat

Topological drawings are natural representations of graphs in the plane, where vertices are represented by points, and edges by curves connecting the points. Topological drawings of complete graphs and of complete bipartite graphs have been…

Computational Geometry · Computer Science 2017-02-10 Jean Cardinal , Stefan Felsner