Title
Obstacle Numbers of Graphs
Abstract
An obstacle representation of a graph G is a drawing of G in the plane with straight-line edges, together with a set of polygons (respectively, convex polygons) called obstacles, such that an edge exists in G if and only if it does not intersect an obstacle. The obstacle number (convex obstacle number) of G is the smallest number of obstacles (convex obstacles) in any obstacle representation of G. In this paper, we identify families of graphs with obstacle number 1 and construct graphs with arbitrarily large obstacle number (convex obstacle number). We prove that a graph has an obstacle representation with a single convex k-gon if and only if it is a circular arc graph with clique covering number at most k in which no two arcs cover the host circle. We also prove independently that a graph has an obstacle representation with a single segment obstacle if and only if it is the complement of an interval bigraph.
Year
DOI
Venue
2010
10.1007/s00454-009-9233-8
Discrete & Computational Geometry
Keywords
Field
DocType
Obstacle number,Convex obstacle number,Circular arc graph,Proper circular arc graph,Non-double-covering circular arc graph,Interval bigraph,Visibility graph
Discrete mathematics,Topology,Obstacle,Block graph,Combinatorics,Line graph,Crossing number (graph theory),Visibility graph,Circular-arc graph,Mathematics,Planar graph,Complement graph
Journal
Volume
Issue
ISSN
44
1
0179-5376
Citations 
PageRank 
References 
10
0.81
7
Authors
3
Name
Order
Citations
PageRank
Hannah Alpert1163.47
Christina Koch2142.21
Joshua D. Laison3387.08