Abstract Information systems have to deal with an increasing amount of data that is
heterogeneous, unstructured, or incomplete. In order to align and complete data, systems …

Recent years have seen an increasing interest in ontology-mediated query answering, in
which the semantic knowledge provided by an ontology is exploited when querying data …

We give a solution to the succinctness problem for the size of first-order rewritings of
conjunctive queries in ontology-based data access with ontology languages such as OWL 2 …

Querying inconsistent ontologies is an intriguing new problem that gave rise to a flourishing
research activity in the description logic (DL) community. The computational complexity of …

As more and more data is being generated by sensor networks, social media and
organizations, the Web interlinking this wealth of information becomes more complex. This is …

We consider instance queries mediated by an ontology expressed in the expressive DL
ALCHIO with closed predicates. We observe that such queries are non-monotonic and …

OWL 2 EL is a popular ontology language that supports role inclusions--axioms of the form
S1... Sn⊆ S that capture compositional properties of roles. Role inclusions closely …

The chase procedure, originally introduced for checking implication of database constraints,
and later on used for computing data exchange solutions, has recently become a central …

The goal of this paper is to understand the relative expressiveness of the query language in
which queries are specified by a set of guarded (disjunctive) tuple-generating dependencies …

• What is Datalog±and what are its advantages? Datalog±is a rule-based formalism that
combines the advantages of logic programming in Datalog with features for expressing …