Properties of chromatic polynomials of hypergraphs not held for chromatic polynomials of graphs
Abstract
In this paper, we present some properties on chromatic polynomials of hypergraphs which do not hold for chromatic polynomials of graphs. We first show that chromatic polynomials of hypergraphs have all integers as their zeros and contain dense real zeros in the set of real numbers. We then prove that for any multigraph , the number of totally cyclic orientations of is equal to the value of , where is the chromatic polynomial of a hypergraph which is constructed from . Finally we show that the multiplicity of root "" of may be at least for some connected hypergraphs , and the multiplicity of root "" of may be for some connected and separable hypergraphs and may be for some connected and non-separable hypergraphs .
Keywords
Cite
@article{arxiv.1611.04245,
title = {Properties of chromatic polynomials of hypergraphs not held for chromatic polynomials of graphs},
author = {Ruixue Zhang and Fengming Dong},
journal= {arXiv preprint arXiv:1611.04245},
year = {2017}
}
Comments
3 figures, 22 pages, 48 references. Accepted for publication in the European Journal of Combinatorics