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Knowledge Representation and Reasoning for the Semantic Web – OWL 2 Rules

a tutorial at KI 2009, Paderborn, Germany, September 15 2009, 9:00–12:30 a.m.

Speakers: Pascal Hitzler, Markus Krötzsch, Sebastian Rudolph


The revision 2 of the Web Ontology Language OWL is much richer than its predecessor OWL 1.0 with respect to modelling with rules. In particular, a significant portion of OWL 2 DL is already expressible using rules (called SROIQ Rules). The tractable profile OWL 2 EL can be extended by rules - within OWL 2 DL - while retaining tractability. Further rules lying outside OWL 2 DL, in particular a generalization of DL-safe Datalog rules, can further be added while still retaining tractability, resulting in a language called ELP, which covers all three tractable profiles of OWL 2. ELP in turn can be extended by local closed-world reasoning such that data complexity still remains polynomial.

This tutorial introduces OWL 2 and the abovementioned rules fragments and extensions in detail. It is aimed for the theoretician as well as the ontology engineer who would like to learn about the intimate relationship between OWL 2 and rules.


In this course, we focus on logical aspects of OWL and rules, using description logic syntax for introducing OWL 2. Readers who prefer a more RDF-centric view can find materials with alternative introductions to OWL 2 on our slides page.


Speaker Biographies

PD Dr. Pascal Hitzler is assistant professor at the University of Karlsruhe (TH), Germany. His research interests comprise Semantic Web, neural-symbolic integration, knowledge representation and reasoning, and mathematical foundations of artificial intelligence. For further information please see

M.Sc. Markus Krötzsch is a researcher at the University of Karlsruhe (TH), Germany, where he is currently working on his PhD thesis. His research interests involve knowledge representation on the Semantic Web, the logical foundations thereof, and the efficient processing of such knowledge. He is also the lead developer of Semantic MediaWiki and maintainer of the website Fur further information, please see

Dr. Sebastian Rudolph is assistant professor at the University of Karlsruhe (TH), Germany. His research interests include knowledge specification and reasoning, logic, algebra, complexity theory as well as semantic search and NLP aspects of knowledge acquisition. He is program chair of the International Conference on Conceptual Structures 2009 and of the International Conference on Formal Concept Analysis 2009. For further information, please see