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 …

We investigate graph transformations, defined using Datalog-like rules based on acyclic
conjunctive two-way regular path queries (acyclic C2RPQs), and we study two fundamental …

Recently, the field of knowledge representation is drawing a lot of inspiration from database
theory. In particular, in the area of description logics and ontology languages, interest has …

We propose a novel use of ontologies to aid the on-demand design of data-centric systems.
By means of a process that we call focusing, a schema for a (possibly knowledge-enriched) …

We study the description logic SQ with number restrictions applicable to transitive roles,
extended with either nominals or inverse roles. We show tight 2EXPTIME upper bounds for …

Abstract Reasoning with existential rules typically consists of checking whether a Boolean
conjunctive query is satisfied by all models of a first-order sentence having the form of a …

We investigate the problem of finite entailment of ontology-mediated queries. We consider
the expressive query language, unions of conjunctive regular path queries (UCRPQs) …

The management of data uncertainty can lead to intractability, in the case of probabilistic
databases, or even undecidability, in the case of open-world reasoning under logical rules …

Open-world query answering is the problem of deciding, given a set of facts, conjunction of
constraints, and query, whether the facts and constraints imply the query. This amounts to …

We introduce and investigate the expressive description logic (DL) ALCSCC++, in which the
global and local cardinality constraints introduced in previous papers can be mixed. On the …