Tree Automata and XPath on Compressed Trees

The complexity of various membership problems for tree automata on compressed trees is analyzed. Two compressed representations are considered: dags, which allow to share identical subtrees in a tree, and straight-line contextfree tree grammars, which moreover allow to share identical intermediate parts of a tree. Several completeness results for the classes NL, P, and PSPACE are obtained. Finally, the complexity of the XPath evaluation problem on trees that are compressed via straight-line context-free tree grammars is investigated.

• Type: Conference
• Year: 2005
• Where: WIA
• Authors: Markus Lohrey, Sebastian Maneth
• Keywords: Artificial Intelligence, Straight-line Context-free Tree, Straight-line Contextfree Tree, Tree Grammars, WIA 2005