On XPath with transitive axes and data tests

Diego Figueira (1)

1 LFCS - Laboratory for the Foundations of Computer Science [Edinburgh]

We study the satisfiability problem for XPath with data equality tests. XPath is a node selecting language for XML documents whose satisfiability problem is known to be unde-cidable, even for very simple fragments. However, we show that the satisfiability for XPath with the rightward, leftward and downward reflexive-transitive axes (namely following-sibling-or-self, preceding-sibling-or-self, descendant-or-self) is decidable. Our algorithm yields a complexity of 3ExpSpace, and we also identify an expressive-equivalent normal form for the logic for which the satisfiability problem is in 2Exp-Space. These results are in contrast with the undecidabil-ity of the satisfiability problem as soon as we replace the reflexive-transitive axes with just transitive (non-reflexive) ones.

Mots clés: reflexive transitive axes; unranked unordered tree; XML; XPath; data-tree; infinite alphabet; data values

Domaines: Base de données [cs.DB]; Théorie et langage formel [cs.FL]; Mathématique discrète [cs.DM]; Logique en informatique [cs.LO]

Diego Figueira. On XPath with transitive axes and data tests. ACM SIGMOD-SIGACT-SIGART Symposium on Principles of Database Systems (PODS), Jun 2013, New York, NY, United States. ⟨10.1145/2463664.2463675⟩. ⟨hal-01795148⟩