eng
Schloss Dagstuhl – Leibniz-Zentrum für Informatik
Leibniz International Proceedings in Informatics
1868-8969
2016-02-16
32:1
32:14
10.4230/LIPIcs.STACS.2016.32
article
Canonizing Graphs of Bounded Tree Width in Logspace
Elberfeld, Michael
Schweitzer, Pascal
Graph canonization is the problem of computing a unique representative, a canon, from the isomorphism class of a given graph. This implies that two graphs are isomorphic exactly if their canons are equal. We show that graphs of bounded tree width can be canonized in deterministic logarithmic space (logspace). This implies that the isomorphism problem for graphs of bounded tree width can be decided in logspace. In the light of isomorphism for trees being hard for the complexity class logspace, this makes the ubiquitous classes of graphs of bounded tree width one of the few classes of graphs for which the complexity of the isomorphism problem has been exactly determined.
https://drops.dagstuhl.de/storage/00lipics/lipics-vol047-stacs2016/LIPIcs.STACS.2016.32/LIPIcs.STACS.2016.32.pdf
algorithmic graph theory
computational complexity
graph isomorphism
logspace
tree width