English

On colouring point visibility graphs

Computational Geometry 2017-06-27 v2

Abstract

In this paper we show that it can be decided in polynomial time whether or not the visibility graph of a given point set is 4-colourable, and such a 4-colouring, if it exists, can also be constructed in polynomial time. We show that the problem of deciding whether the visibility graph of a point set is 5-colourable, is NP-complete. We give an example of a point visibility graph that has chromatic number 6 while its clique number is only 4.

Keywords

Cite

@article{arxiv.1610.00952,
  title  = {On colouring point visibility graphs},
  author = {Ajit Arvind Diwan and Bodhayan Roy},
  journal= {arXiv preprint arXiv:1610.00952},
  year   = {2017}
}
R2 v1 2026-06-22T16:09:58.718Z