Stefan Borgwardt

TL;DR: It is shown that undecidability may arise even if only crisp axioms are considered, and the effectiveness of this approach is demonstrated by strengthening all previously-known undecIDability results and providing new ones.

TL;DR: This paper presents a proof framework that allows for a near-universal classification of fuzzy DLs according to the decidability of their consistency problem, and provides matchingDecidability results for most of the remaining logics.

TL;DR: This work investigates an extension of OBDA to the temporal case, and considers an extensions of the well-known propositional temporal logic LTL where conjunctive queries can occur in place of propositional variables, and uses the prototypical expressive DL $\mathcal{ALC}$.

TL;DR: Ontology-based data access generalizes query answering in relational databases and allows to query a database by using the language of an ontology, abstracting from the actual relations of the database.

TL;DR: This paper proposes a generic temporal query language that combines linear temporal logic with queries over ontologies and shows that, if atemporal queries are rewritable in the sense described above, then the corresponding temporal queries are also rewroteable such that they can answer them over a temporal database.