20 search results - page 4 / 4 » Circular Chromatic Number of Hypergraphs |
JCT
2007
13 years 5 months ago
2007
In Ziegler (2002), the second author presented a lower bound for the chromatic numbers of hypergraphs KGr sssS, “generalized r-uniform Kneser hypergraphs with intersection multi...
CORR
2008
Springer
13 years 5 months ago
2008
Springer
Map vertices of a graph to (not necessarily distinct) points of the plane so that two adjacent vertices are mapped at least a unit distance apart. The plane-width of a graph is th...
IPL
2007
13 years 5 months ago
2007
Abstract. The intention of this note is to motivate the researchers to study Hadwiger’s conjecture for circular arc graphs. Let η(G) denote the largest clique minor of a graph G...
FOCS
2002
IEEE
13 years 10 months ago
2002
IEEE
We prove that coloring a 3-uniform 2-colorable hypergraph with c colors is NP-hard for any constant c. The best known algorithm [20] colors such a graph using O(n1/5 ) colors. Our...
APPROX
2004
Springer
13 years 10 months ago
2004
Springer
A simple first moment argument shows that in a randomly chosen k-SAT formula with m clauses over n boolean variables, the fraction of satisfiable clauses is 1−2−k +o(1) as m/...