Abstract Knowledge graphs such as Yago and Freebase have become a powerful asset for
enhancing search, and are being intensively used in both academia and industry. Many …

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 …

We study ELI queries (ELIQs) in the presence of ontologies formulated in the description
logic DL-Lite. For the dialect DL-LiteH, we show that ELIQs have a frontier (set of least …

Ontology-based data access (OBDA) is regarded as a key ingredient of the new generation
of information systems. In the OBDA paradigm, an ontology defines a high-level global …

An increasing number of applications rely on RDF, OWL 2, and SPARQL for storing and
querying data. SPARQL, however, is not targeted towards end-users, and suitable query …

Ontology-mediated query answering (OMQA) is a new paradigm in data management that
seeks to exploit the semantic knowledge expressed in ontologies to improve query …

Ontology-based data access (OBDA) generalizes query answering in relational databases. It
allows to query a database by using the language of an ontology, abstracting from the actual …

We study the enumeration of answers to ontology-mediated queries (OMQs) where the
ontology is a set of guarded TGDs or formulated in the description logic ELI and the query is …

We investigate the problem of learning description logic (DL) ontologies in Angluin et al.'s
framework of exact learning via queries posed to an oracle. We consider membership …