The inclusion of Regular Expressions (REs) is the kernel of any subtype checking algorithm for XML schema languages. XML applications would benefit from the extension of REs with interleaving and counting, but this is not feasible in general, since ...

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 maximum number of tuples from db without ever selecting two tuples that agree ...

We report on a recently introduced family of expressive extensions of Datalog, called Datalog^±, which is a new framework for representing ontological axioms in form of integrity constraints, and for query answering under such constraints. Datalog± is ...