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Properties of chromatic polynomials of hypergraphs not held for chromatic polynomials of graphs

Authors :
Zhang, Ruixue
Dong, Fengming
Publication Year :
2016

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 $G=(V,E)$, the number of totally cyclic orientations of $G$ is equal to the value of $|P(H,-1)|$, where $P(H,\lambda)$ is the chromatic polynomial of a hypergraph $H$ which is constructed from $G$. Finally we show that the multiplicity of root "$0$" of $P(H,\lambda)$ may be at least $2$ for some connected hypergraphs $H$, and the multiplicity of root "$1$" of $P(H,\lambda)$ may be $1$ for some connected and separable hypergraphs $H$ and may be $2$ for some connected and non-separable hypergraphs $H$.<br />Comment: 3 figures, 22 pages, 48 references. Accepted for publication in the European Journal of Combinatorics

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.1611.04245
Document Type :
Working Paper