10 citations · 14 across the 6 of their papers we have counts for
8 papers
Learning Tree Pattern Transformations
Daniel Neider, Leif Sabellek, Johannes Schmidt +2
Explaining why and how a tree structurally differs from another tree is a question that is encountered throughout computer science, including in understanding tree-st…
Parikh Automata on Finite and Infinite Words
Mario Grobler, Leif Sabellek, Sebastian Siebertz
We study Parikh automata on finite and infinite words. First we establish some results for Parikh automata on finite words. Following, we present several definitions of Parikh auto…
Description Logics with Abstraction and Refinement
Carsten Lutz, Lukas Schulze
Ontologies often require knowledge representation on multiple levels of abstraction, but description logics (DLs) are not well-equipped for supporting this. We propose an extension…
Parikh Automata on Infinite Words
Mario Grobler, Leif Sabellek, Sebastian Siebertz
Parikh automata on finite words were first introduced by Klaedtke and Rueß [Automata, Languages and Programming, 2003]. In this paper, we introduce several variants of Parikh autom…
Ontology-Mediated Querying on Databases of Bounded Cliquewidth
Carsten Lutz, Leif Sabellek, Lukas Schulze
We study the evaluation of ontology-mediated queries (OMQs) on databases of bounded cliquewidth from the viewpoint of parameterized complexity theory. As the ontology language, we…
How to Approximate Ontology-Mediated Queries
Anneke Haga, Carsten Lutz, Leif Sabellek +1
We introduce and study several notions of approximation for ontology-mediated queries based on the description logics ALC and ALCI. Our approximations are of two kinds: we may (1)…
Query Expressibility and Verification in Ontology-Based Data Access
Carsten Lutz, Johannes Marti, Leif Sabellek
In ontology-based data access, multiple data sources are integrated using an ontology and mappings. In practice, this is often achieved by a bootstrapping process, that is, the ont…
A Complete Classification of the Complexity and Rewritability of Ontology-Mediated Queries based on the Description Logic EL
Carsten Lutz, Leif Sabellek
We provide an ultimately fine-grained analysis of the data complexity and rewritability of ontology-mediated queries (OMQs) based on an EL ontology and a conjunctive query (CQ). Ou…