English
Related papers

Related papers: Graphs with Plane Outside-Obstacle Representations

200 papers

A universal representation theorem is derived that shows any graph is the intersection graph of one chordal graph, a number of co-bipartite graphs, and one unit interval graph. Central to the the result is the notion of the clique cover…

Combinatorics · Mathematics 2015-04-21 Farhad Shahrokhi

While orthogonal drawings have a long history, smooth orthogonal drawings have been introduced only recently. So far, only planar drawings or drawings with an arbitrary number of crossings per edge have been studied. Recently, a lot of…

The disjoint convex obstacle number of a graph G is the smallest number h such that there is a set of h pairwise disjoint convex polygons (obstacles) and a set of n points in the plane (corresponding to V(G)) so that a vertex pair uv is an…

Discrete Mathematics · Computer Science 2011-09-13 Radoslav Fulek , Noushin Saeedi , Deniz Sarioz

In \emph{smooth orthogonal layouts} of planar graphs, every edge is an alternating sequence of axis-aligned segments and circular arcs with common axis-aligned tangents. In this paper, we study the problem of finding smooth orthogonal…

Computational Geometry · Computer Science 2013-12-13 Md. Jawaherul Alam , Michael A. Bekos , Michael Kaufmann , Philipp Kindermann , Stephen G. Kobourov , Alexander Wolff

The crossing number of a graph is the least number of crossings over all drawings of the graph in the plane. Computing the crossing number of a given graph is NP-hard, but fixed-parameter tractable (FPT) with respect to the natural…

Data Structures and Algorithms · Computer Science 2025-04-14 Yasuaki Kobayashi , Yuto Okada , Alexander Wolff

In a rectilinear dual of a planar graph vertices are represented by simple rectilinear polygons and edges are represented by side-contact between the corresponding polygons. A rectilinear dual is called a cartogram if the area of each…

Discrete Mathematics · Computer Science 2012-01-05 Md. Jawaherul Alam , Therese Biedl , Stefan Felsner , Michael Kaufmann , Stephen G. Kobourov , Torsten Ueckerdt

A string graph is the intersection graph of curves in the plane. Kratochv\'il previously showed the existence of infinitely many obstacles: graphs that are not string graphs but for which any edge contraction or vertex deletion produces a…

Combinatorics · Mathematics 2025-09-03 Maria Chudnovsky , David Eppstein , David Fischer

We consider hypergraph visualizations that represent vertices as points in the plane and hyperedges as curves passing through the points of their incident vertices. Specifically, we consider several different variants of this problem by (a)…

Computational Geometry · Computer Science 2025-06-09 Alexander Dobler , Stephen Kobourov , Debajyoti Mondal , Martin Nöllenburg

An IC-plane graph is a topological graph where every edge is crossed at most once and no two crossed edges share a vertex. We show that every IC-plane graph has a visibility drawing where every vertex is an L-shape, and every edge is either…

Computational Geometry · Computer Science 2019-09-04 Giuseppe Liotta , Fabrizio Montecchiani

We introduce and study a new graph representation where vertices are embedded in three or more dimensions, and in which the edges are drawn on the projections onto the axis-parallel planes. We show that the complete graph on $n$ vertices…

Discrete Mathematics · Computer Science 2020-10-06 N. R. Aravind , Udit Maniyar

We introduce the class of interval $H$-graphs, which is the generalization of interval graphs, particularly interval bigraphs. For a fixed graph $H$ with vertices $a_1,a_2,\dots,a_k$, we say that an input graph $G$ with given partition…

Discrete Mathematics · Computer Science 2025-03-04 Haiko Müller , Arash Rafiey

A graph is an opposition graph, respectively, a coalition graph, if it admits an acyclic orientation which puts the two end-edges of every chordless 4-vertex path in opposition, respectively, in the same direction. Opposition and coalition…

Discrete Mathematics · Computer Science 2015-07-03 Van Bang Le , Thomas Podelleck

A graph is a mathematical object consisting of a set of vertices and a set of edges connecting vertices. Graphs can be drawn on paper in various ways, but until recently all published methods of drawing graphs have had undesirable…

Human-Computer Interaction · Computer Science 2014-05-22 Bob Blakley , G R Blakley , Sean M Blakley

In a planar L-drawing of a directed graph (digraph) each edge e is represented as a polyline composed of a vertical segment starting at the tail of e and a horizontal segment ending at the head of e. Distinct edges may overlap, but not…

Computational Geometry · Computer Science 2020-08-19 Patrizio Angelini , Steven Chaplick , Sabine Cornelsen , Giordano Da Lozzo

Eternal vertex cover problem is a variant of the classical vertex cover problem modeled as a two player attacker-defender game. Computing eternal vertex cover number of graphs is known to be NP-hard in general and the complexity status of…

Discrete Mathematics · Computer Science 2022-01-19 Jasine Babu , K. Murali Krishnan , Veena Prabhakaran , Nandini J. Warrier

A bar 1-visibility drawing of a graph $G$ is a drawing of $G$ where each vertex is drawn as a horizontal line segment called a bar, each edge is drawn as a vertical line segment where the vertical line segment representing an edge must…

Discrete Mathematics · Computer Science 2013-02-21 Shaheena Sultana , Md. Saidur Rahman , Arpita Roy , Suraiya Tairin

Topological drawings are representations of graphs in the plane, where vertices are represented by points, and edges by simple curves connecting the points. A drawing is simple if two edges intersect at most in a single point, either at a…

Computational Geometry · Computer Science 2022-09-08 Alfredo García , Alexander Pilz , Javier Tejel

A planar orthogonal drawing of a planar 4-graph G (i.e., a planar graph with vertex-degree at most four) is a crossing-free drawing that maps each vertex of G to a distinct point of the plane and each edge of $G$ to a sequence of horizontal…

Computational Geometry · Computer Science 2022-05-17 Walter Didimo , Michael Kaufmann , Giuseppe Liotta , Giacomo Ortali

A graph is outerplanar if it can be embedded in a plane such that all vertices lie on its outer face. The outerplanar Tur\'{a}n number of a given graph $H$, denoted by ${\rm ex}_{\mathcal{OP}}(n,H)$, is the maximum number of edges over all…

Combinatorics · Mathematics 2021-10-22 Longfei Fang , Mingqing Zhai

IC-planar graphs are those graphs that admit a drawing where no two crossed edges share an end-vertex and each edge is crossed at most once. They are a proper subfamily of the 1-planar graphs. Given an embedded IC-planar graph $G$ with $n$…

Computational Geometry · Computer Science 2016-07-19 Franz J. Brandenburg , Walter Didimo , William S. Evans , Philipp Kindermann , Giuseppe Liotta , Fabrizio Montecchiani