Conjunctive Visibly-Pushdown Path Queries

Martin Lange, Étienne Lozes

Abstract: We investigate an extension of conjunctive regular path queries in which path properties and path relations are defined by visibly pushdown automata. We study the problem of query evaluation for extended conjunctive visibly pushdown path queries and their subclasses, and give a complete picture of their combined and data complexity. In particular, we introduce a weaker notion called extended conjunctive reachability queries for which query evaluation has a polynomial data complexity. We also show that query containment is decidable in 2-EXPTIME for (non-extended) conjunctive visibly pushdown path queries.