Description Logic programs (DL-programs) are a prominent approach for a loose coupling of rules and ontologies, which has become a topic of increased interest. When computing answer sets of a DL-program, special DL-atoms, which provide query interface to an ontology, are evaluated under a possibly changing input that gives a context for the evaluation. Many different such contexts may exist and...

In previous work [8] we proposed an extension for the belief base of AgentSpeak agents based on Description Logic, aiming at enabling agent oriented programming to cope with recently proposed technologies for the Semantic Web. In such an extension an agent belief base contains the definition of complex concepts, besides specific factual knowledge. The foreseen advantages are: (i) more expressiv...

DL-Lite is a family of Description Logics (DLs) whose aim is to capture some of the most popular conceptual modeling formalisms, such as Entity-Relationship model [4] and UML class diagrams1, while preserving the tractability of the most important reasoning tasks, such as ontology satisfiability and query answering of arbitrary (union of) conjunctive queries (ground and not ground). More specif...

Query rewriting has become a very prominent tool for efficiently implementing ontology-mediated querying in practice. The technique was originally introduced in the context of DL-Lite [4], but is now increasingly being used also for more expressive DLs. While rewritings are not guaranteed to exist beyond DL-Lite, the simple structure of ontologies that emerge from practical applications gives h...

In Description Logics (DLs) and in the ontology-based data access (OBDA) scenario, the use of actual datatypes (such as those adopted in DBMSs) has received only limited attention, although datatypes, with their predefined semantics, might have a substantial impact on the computational complexity of inference in ontology systems. In this work we aim at overcoming these limitations, and study th...