The Isomorphism Problem for k-Trees Is Complete for Logspace

Abstract. We show that k-tree isomorphism can be decided in logarithmic space by giving a logspace canonical labeling algorithm. This improves over the previous StUL upper bound and matches the lower bound. As a consequence, the isomorphism, the automorphism, as well as the canonization problem for k-trees are all complete for deterministic logspace. We also show that even simple structural properties of k-trees are complete for logspace.

• Type: Conference
• Year: 2009
• Where: MFCS
• Authors: Johannes Köbler, Sebastian Kuhnert
• Keywords: Canonical Labeling Algorithm, K-tree Isomorphism, MFCS 2009, StUL Upper Bound, Theoretical Computer Science