This article deals with consistent query answering to conjunctive queries under primary key constraints. The repairs of an inconsistent database db are obtained by selecting a max...
We study the problem of deciding whether two ontologies are inseparable w.r.t. a signature Σ, i.e., whether they have the same consequences in the signature Σ. A special case is...
We study the problem of answering queries over sources with limited access patterns. The problem is to decide whether a given query Q is feasible, i.e., equivalent to an executable...
The class of unions of conjunctive queries (UCQ) has been shown to be particularly well-behaved for data exchange; its certain answers can be computed in polynomial time (in terms...
Query folding refers to the activity of determining if and how a query can be answered using a given set of resources, which might be materialized views, cached results of previou...