English

Unit Disk Representations of Embedded Trees, Outerplanar and Multi-Legged Graphs

Computational Geometry 2021-08-27 v2 Discrete Mathematics

Abstract

A unit disk intersection representation (UDR) of a graph GG represents each vertex of GG as a unit disk in the plane, such that two disks intersect if and only if their vertices are adjacent in GG. A UDR with interior-disjoint disks is called a unit disk contact representation (UDC). We prove that it is NP-hard to decide if an outerplanar graph or an embedded tree admits a UDR. We further provide a linear-time decidable characterization of caterpillar graphs that admit a UDR. Finally we show that it can be decided in linear time if a lobster graph admits a weak UDC, which permits intersections between disks of non-adjacent vertices.

Keywords

Cite

@article{arxiv.2103.08416,
  title  = {Unit Disk Representations of Embedded Trees, Outerplanar and Multi-Legged Graphs},
  author = {Sujoy Bhore and Maarten Löffler and Soeren Nickel and Martin Nöllenburg},
  journal= {arXiv preprint arXiv:2103.08416},
  year   = {2021}
}

Comments

34 Pages, 19 Figures, An extended abstract of this paper will appear in the Proceedings of GD 2021