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DAM

2011

9 years 6 months ago
2011

An arc of a graph is an oriented edge and a 3-arc is a 4-tuple (v, u, x, y) of vertices such that both (v, u, x) and (u, x, y) are paths of length two. The 3-arc graph of a graph ...

ALGORITHMICA

2010

9 years 10 months ago
2010

The problem of computing the chromatic number of a P5-free graph (a graph which contains no path on 5 vertices as an induced subgraph) is known to be NP-hard. However, we show tha...

MP

2010

9 years 10 months ago
2010

The Lov´asz theta number of a graph G can be viewed as a semideﬁnite programming relaxation of the stability number of G. It has recently been shown that a copositive strengthe...

JGT

2010

9 years 10 months ago
2010

In 1966 Erd˝os and Hajnal proved that the chromatic number of graphs whose

JGT

2010

9 years 10 months ago
2010

Hadwiger’s conjecture states that every graph with chromatic number χ has a clique minor of size χ. In this paper we prove a weakened version of this conjecture for the class ...

DM

1998

9 years 11 months ago
1998

Suppose G is a graph. The chromatic Ramsey number rc(G) of G is the least integer m such that there exists a graph F of chromatic number m for which the following is true: For any...

DM

2002

9 years 11 months ago
2002

A simple characterization of the 3, 4, or 5-colorable Eulerian triangulations of the projective plane is given. Key words: Projective plane, triangulation, coloring, Eulerian grap...

ENDM

2000

9 years 11 months ago
2000

We propose a new exact algorithm for finding the chromatic number of a graph G. The algorithm attempts to determine the smallest possible induced subgraph G' of G which has t...

DM

2000

9 years 11 months ago
2000

Erdos proved that there are graphs with arbitrarily large girth and chromatic number. We study the extension of this for generalized chromatic numbers. Generalized graph coloring d...

ARSCOM

2004

9 years 11 months ago
2004

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 pr...