Answering queries over an incomplete database w.r.t. a set of constraints is an important computational task with applications in fields as diverse as information integration and ...
W3C currently extends the SPARQL query language with so-called entailment regimes, which define how queries are evaluated using logical entailment relations. We describe a sound a...
We study the complexity of the problem of answering queries using materialized views. This problem has attracted a lot of attention recently because of its relevance in data integ...
A serious shortcoming of many Description Logic based knowledge representation systems is the inadequacy of their query languages. In this paper we present a novel technique that ...