| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4654476 | European Journal of Combinatorics | 2006 | 9 Pages |
Abstract
A class CC of graphs is said to be HH-bounded if each graph in the class CC admits a homomorphism to HH. We give a general necessary and sufficient condition for the existence of bounds with special local properties. This gives a new proof of the Häggkvist–Hell theorem [R. Häggkvist, P. Hell, Universality of A-mote graphs, European J. Combin. 14 (1993) 23–27] and implies several cases of the existence of triangle free bounds for planar graphs.
Related Topics
Physical Sciences and Engineering
Mathematics
Discrete Mathematics and Combinatorics
Authors
Timothy Marshall, Reza Nasraser, Jaroslav Nešetřil,