9 search results - page 1 / 2 » Hadwiger's conjecture for quasi-line graphs |
IPL
2007
13 years 10 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...
JGT
2010
13 years 9 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
2006
13 years 11 months ago
2006
Assuming that every proper minor closed class of graphs contains a maximum with respect to the homomorphism order, we prove that such a maximum must be homomorphically equivalent ...
COMBINATORICS
2002
13 years 10 months ago
2002
Suppose G is r-colorable and P V (G) is such that the components of G[P] are far apart. We show that any (r + s)-coloring of G[P] in which each component is s-colored extends to ...
JGT
2008
13 years 10 months ago
2008