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 …

The restricted chase is a sound and complete algorithm for conjunctive query answering
over ontologies of disjunctive existential rules. We develop acyclicity conditions to ensure its …

Conjunctive regular path queries are an expressive extension of the well-known class of
conjunctive queries. Such queries have been extensively studied in the (graph) database …

A prime application of description logics is ontology-mediated query answering, with the
query language often reaching far beyond instance queries. Here, we investigate this task …

We investigate ontology-based query answering for data that are both temporal and
probabilistic, which might occur in contexts such as stream reasoning or situation …

The unary negation fragment of first-order logic (UNFO) has recently been proposed as a
generalization of modal logic that shares many of its good computational and model …

Abstract In Ontology-Based Data Access (OBDA), user queries are evaluated over a set of
facts under the open world assumption, while taking into account background knowledge …

We investigate the data complexity of the satisfiability problem for the very expressive
description logic ZOIQ (aka ALCHb Self reg OIQ) over quasi-forests and establish its NP …

Ontology-mediated query answering is concerned with the problem of answering queries
over knowledge bases consisting of a database instance and an ontology. While most work …