Title
Clique colourings of geometric graphs
Abstract
A clique colouring of a graph is a colouring of the vertices such that no maximal clique is monochromatic (ignoring isolated vertices). The least number of colours in such a colouring is the clique chromatic number. Given n points x(1), ..., x(n), in the plane, and a threshold r > 0, the corresponding geometric graph has vertex set {v(1), ... , v(n)}, and distinct v(i) and v(j) are adjacent when the Euclidean distance between x(i) and x(j) is at most r. We investigate the clique chromatic number of such graphs. We first show that the clique chromatic number is at most 9 for any geometric graph in the plane, and briefly consider geometric graphs in higher dimensions. Then we study the asymptotic behaviour of the clique chromatic number for the random geometric graph g(n, r) in the plane, where n random points are independently and uniformly distributed in a suitable square. We see that as r increases from 0, with high probability the clique chromatic number is 1 for very small r, then 2 for small r, then at least 3 for larger r, and finally drops back to 2.
Year
DOI
Venue
2018
10.37236/7159
ELECTRONIC JOURNAL OF COMBINATORICS
DocType
Volume
Issue
Journal
25
4
ISSN
Citations 
PageRank 
1077-8926
0
0.34
References 
Authors
10
3
Name
Order
Citations
PageRank
Colin McDiarmid11071167.05
Dieter Mitsche214126.08
Pawel Pralat323448.16