Results 201 to 210 of about 3,787 (214)

Density of the circular chromatic numbers of series‐parallel graphs

Journal of Graph Theory, 2004
AbstractSuppose G is a series‐parallel graph. It was proved in 3 that either χc(G) = 3 or χc(G) ≤ 8/3. So none of the rationals in the interval (8/3, 3) is the circular chromatic number of a series‐parallel graph. This paper proves that for every rational r ∈ [2, 8/3] ∪ {3} there exists a series‐parallel graph G with χc(G) = r. © 2004 Wiley Periodicals,
Zhishi Pan, Xuding Zhu
openaire   +1 more source

A combinatorial proof for the circular chromatic number of Kneser graphs

Journal of Combinatorial Optimization, 2015
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Daphne Der-Fen Liu, Xuding Zhu
openaire   +1 more source

Circular chromatic numbers of some reduced Kneser graphs

Journal of Graph Theory, 2002
AbstractThe vertex set of the reduced Kneser graph KG2(m,2) consists of all pairs {a,b} such that a, bε{1,2,…,m} and 2≤|a−b|≤m−2. Two vertices are defined to be adjacent if they are disjoint. We prove that, if m≥4 and m≠5, then the circular chromatic number of KG2(m,2) is equal to m−2, its ordinary chromatic number. © 2002 Wiley Periodicals, Inc.
Ko-Wei Lih, Daphne Der-Fen Liu
openaire   +2 more sources

Circulant distant two labeling and circular chromatic number

Ars Comb., 2003
Distance constrained labelings with \(k\) parameters assign labels to vertices of a given graph such that vertices at distance \(i\leq k\) get labels that differ by at least the prespecified \(i\)th parameter. In the paper values for the minimum span of distance constrained labelings with two constraints of trees and of cycles in the cyclic metric ...
Daphne Der-Fen Liu, Xuding Zhu
openaire   +1 more source

The circular chromatic number of series-parallel graphs

Journal of Graph Theory, 2000
Xuding Zhu
exaly  

A topological lower bound for the circular chromatic number of Schrijver graphs

Journal of Graph Theory, 2005
Frédéric Meunier
exaly  

Circular chromatic number of distance graphs with distance sets of cardinality 3

Journal of Graph Theory, 2002
Xuding Zhu
exaly  

The circular chromatic index of graphs of high girth

Journal of Combinatorial Theory Series B, 2007
Riste Škrekovski, Daniel Kral, Xuding Zhu   +2 more
exaly  

Circular chromatic index of type 1 Blanuša snarks

Journal of Graph Theory, 2008
Jan Mazák
exaly  

k-Regular graphs with the circular chromatic index close tok

Discrete Mathematics, 2014
Edita Máčajová
exaly