Markus Krötzsch

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Semantic MediaWiki is an extension of MediaWiki – a widely used wiki-engine that also powers Wikipedia. Its aim is to make semantic technologies available to a broad community by smoothly integrating them with the established usage of MediaWiki. The software is already used on a number of productive installations world-wide, but the main target remains to(More)
Exercise 8.1. Transform the following concepts into negation normal form: (a) ¬(A u ∀r.B) (b) ¬∀r.∃s.(¬B t ∃r.A) (c) ¬((¬A u ∃r.>) t> 3 s.(A t ¬B)) Exercise 8.2. Apply the tableau algorithm in order to check if the axiom A v B is a logical consequence of the TBox {¬C v B,A u C v ⊥}. Exercise 8.3. Aply the tableau algorithm in order to check satisfiability(More)
We describe an optimised consequence-based procedure for classification of ontologies expressed in a polynomial fragment ELHR+ of the OWL 2 EL profile. A distinguishing property of our procedure is that it can take advantage of multiple processors/cores, which increasingly prevail in computer systems. Our solution is based on a variant of the ‘given clause’(More)
A common perception is that there are two competing visions for the future evolution of the Web: the Semantic Web and Web 2.0. A closer look, though, reveals that the core technologies and concerns of these two approaches are complementary and that each field can and must draw from the other's strengths. We believe that future web applications will retain(More)
We develop inferencing methods for SROEL(⊓,×) – a DL that subsumes the main features of the W3C recommendation OWL EL –, and present a framework for studying materialisation calculi based on datalog. The latter is used to investigate the resource requirements for inferencing, and we can show that certain SROEL(⊓,×) feature combinations must lead to(More)
We introduce ELP as a decidable fragment of the Semantic Web Rule Language (SWRL) that admits reasoning in polynomial time. ELP is based on the tractable description logic EL, and encompasses an extended notion of the recently proposed DL rules for that logic. Thus ELP extends EL with a number of features introduced by the forthcoming OWL 2, such as(More)
Wikidata is the central data management platform of Wikipedia. By the efforts of thousands of volunteers, the project has produced a large, open knowledge base with many interesting applications. The data is highly interlinked and connected to many other datasets, but it is also very rich, complex, and not available in RDF. To address this issue, we(More)