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An outerplanar graph is a planar graph that has a planar drawing with all vertices on the unbounded face. The matching complex of a graph is the simplicial complex whose faces are subsets of disjoint edges of the graph. In this paper we…

Combinatorics · Mathematics 2024-11-08 Margaret Bayer , Marija Jelić Milutinović , Julianne Vega

Vertex splitting replaces a vertex by two copies and partitions its incident edges amongst the copies. This problem has been studied as a graph editing operation to achieve desired properties with as few splits as possible, most often…

Computational Geometry · Computer Science 2023-01-24 Martin Gronemann , Martin Nöllenburg , Anaïs Villedieu

Planar graphs can be represented as intersection graphs of different types of geometric objects in the plane, e.g., circles (Koebe, 1936), line segments (Chalopin \& Gon{\c{c}}alves, 2009), \textsc{L}-shapes (Gon{\c{c}}alves et al, 2018).…

Computational Geometry · Computer Science 2021-06-03 Dibyayan Chakraborty , Kshitij Gajjar

An EPG-representation of a graph $G$ is a collection of paths in a plane square grid, each corresponding to a single vertex of $G$, so that two vertices are adjacent if and only if their corresponding paths share infinitely many points. In…

Discrete Mathematics · Computer Science 2017-11-15 Martin Pergel , Paweł Rzążewski

Beyond-planarity focuses on combinatorial properties of classes of non-planar graphs that allow for representations satisfying certain local geometric or topological constraints on their edge crossings. Beside the study of a specific graph…

Data Structures and Algorithms · Computer Science 2019-08-27 Patrizio Angelini , Michael A. Bekos , Michael Kaufmann , Thomas Schneck

A point visibility graph is a graph induced by a set of points in the plane, where every vertex corresponds to a point, and two vertices are adjacent whenever the two corresponding points are visible from each other, that is, the open…

Computational Geometry · Computer Science 2019-02-05 Jean Cardinal , Udo Hoffmann

A point visibility graph is a graph induced by a set of points in the plane where the vertices of the graph represent the points in the point set and two vertices are adjacent if and only if no other point from the point set lies on the…

Discrete Mathematics · Computer Science 2018-05-17 Anne-Sophie Himmel , Clemens Hoffmann , Pascal Kunz , Vincent Froese , Manuel Sorge

An obstacle representation of a graph G is a set of points on the plane together with a set of polygonal obstacles that determine a visibility graph isomorphic to G. The obstacle number of G is the minimum number of obstacles over all…

Discrete Mathematics · Computer Science 2015-03-17 János Pach , Deniz Sarioz

In a representation of a graph $G$ as an edge intersection graph of paths on a grid (EPG) every vertex of $G$ is represented by a path on a grid and two paths share a grid edge iff the corresponding vertices are adjacent. In a monotonic EPG…

Combinatorics · Mathematics 2023-01-02 Eranda Cela , Elisabeth Gaar

We define the \emph{visual complexity} of a plane graph drawing to be the number of basic geometric objects needed to represent all its edges. In particular, one object may represent multiple edges (e.g., one needs only one line segment to…

Computational Geometry · Computer Science 2018-09-10 Gregor Hültenschmidt , Philipp Kindermann , Wouter Meulemans , André Schulz

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

A graph is \emph{fan-crossing free} if it has a drawing in the plane so that each edge is crossed by independent edges, that is the crossing edges have distinct vertices. On the other hand, it is \emph{fan-crossing} if the crossing edges…

Discrete Mathematics · Computer Science 2020-12-14 Franz J. Brandenburg

An ortho-polygon visibility representation $\Gamma$ of a $1$-plane graph $G$ (OPVR of $G$) is an embedding preserving drawing that maps each vertex of $G$ to a distinct orthogonal polygon and each edge of $G$ to a vertical or horizontal…

Data Structures and Algorithms · Computer Science 2018-08-03 Giuseppe Liotta , Fabrizio Montecchiani , Alessandra Tappini

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 investigate graphs that can be represented as vertex intersections of horizontal and vertical paths in a grid, the so called $B_0$-VPG graphs. Recognizing this class is an NP-complete problem. Although, there exists a polynomial time…

Combinatorics · Mathematics 2015-11-02 L. Alcón , F. Bonomo , M. P. Mazzoleni

An \emph{outer-RAC drawing} of a graph is a straight-line drawing where all vertices are incident to the outer cell and all edge crossings occur at a right angle. If additionally, all crossing edges are either horizontal or vertical, we…

Computational Complexity · Computer Science 2024-11-27 Förster , Julia Katheder , Giacomo Ortali

A \emph{Stick graph} is an intersection graph of axis-aligned segments such that the left end-points of the horizontal segments and the bottom end-points of the vertical segments lie on a `ground line,' a line with slope $-1$. It is an open…

Computational Geometry · Computer Science 2018-08-31 Felice De Luca , Md Iqbal Hossain , Stephen Kobourov , Anna Lubiw , Debajyoti Mondal

Given a set of objects $O$ in the plane, the corresponding intersection graph is defined as follows. Each object defines a vertex and an edge joins two vertices whenever the corresponding objects intersect. We study here the case of unit…

Computational Geometry · Computer Science 2025-12-09 Michael Hoffmann , Tillmann Miltzow , Simon Weber , Lasse Wulf

A $k$-bend path is a non-self-intersecting polyline in the plane made of at most $k+1$ axis-parallel line segments. B$_k$-VPG is the class of graphs which can be represented as intersection graphs of $k$-bend paths in the same plane. In…

Combinatorics · Mathematics 2023-03-07 Sparsh Jain , Sreejith K. Pallathumadam , Deepak Rajendraprasad

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