منابع مشابه
Chromatic polynomials of hypergraphs
In this paper we present some hypergraphs which are chromatically characterized by their chromatic polynomials. It occurs that these hypergraphs are chromatically unique. Moreover we give some equalities for the chromatic polynomials of hypergraphs generalizing known results for graphs and hypergraphs of Read and Dohmen.
متن کاملHypergraphs with Zero Chromatic Threshold
Let F be an r-uniform hypergraph. The chromatic threshold of the family of F free, r-uniform hypergraphs is the infimum of all non-negative reals c such that the subfamily of F -free, r-uniform hypergraphs H with minimum degree at least c (|V (H)| r−1 ) has bounded chromatic number. The study of chromatic thresholds of various graphs has a long history, beginning with the early work of Erdős-Si...
متن کاملCircular Chromatic Number of Hypergraphs
The concept of circular chromatic number of graphs was introduced by Vince(1988). In this paper we define circular chromatic number of uniform hypergraphs and study their basic properties. We study the relationship between circular chromatic number with chromatic number and fractional chromatic number of uniform hypergraphs.
متن کاملOn The Chromatic Number of Geometric Hypergraphs
A finite family R of simple Jordan regions in the plane defines a hypergraph H = H(R) where the vertex set of H is R and the hyperedges are all subsets S ⊂ R for which there is a point p such that S = {r ∈ R|p ∈ r}. The chromatic number of H(R) is the minimum number of colors needed to color the members of R such that no hyperedge is monochromatic. In this paper we initiate the study of the chr...
متن کاملChromatic polynomials of some sunflower mixed hypergraphs
The theory of mixed hypergraph coloring was first introduced by Voloshin in 1993 and has been growing ever since. The proper coloring of a mixed hypergraph H = (X, C,D) is the coloring of the vertex set X so that no D-hyperedge is monochromatic and no C-hyperedge is polychromatic. A mixed hypergraph with hyperedges of type D, C or B is commonly known as a D, C, or B-hypergraph respectively wher...
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ژورنال
عنوان ژورنال: Discrete Applied Mathematics
سال: 2010
ISSN: 0166-218X
DOI: 10.1016/j.dam.2009.09.003