Querying Streaming XML Using Visibly Pushdown Automata

We present a novel solution to streaming XPath query evaluation, capable of supporting forward and reverse axes queries. We show a conversion of an XPath query to a Visibly Pushdown Automaton that preserves the semantics of the query. It was shown in [1] that such a construction results in an automation suitable for efficient streaming query evaluation. We also show that the constructed automaton is polynomial in size of the query when negated predicates are disallowed