[TU Dresden]

Description Logics

Technische Universität Dresden
Institut für Theoretische Informatik
Lehrstuhl für Automatentheorie

Prof. Franz Baader


The Q&A session for the 16th of July has been called off, due to a lack of open questions!

Course Description

Description Logics (DLs) are a successful family of logic-based knowledge representation formalisms, which can be used to represent the conceptual knowledge of an application domain in a structured and formally well-understood way. They are employed in various application domains, such as natural language processing, configuration, and databases, but their most notable success so far is the adoption of the DL-based language OWL as standard ontology language for the semantic web. This course concentrates on designing and analyzing reasoning procedures for DLs. After a short introduction of predecessor formalisms such as semantic networks and frames, it will introduce the basic features of DLs such as concepts, TBoxes and ABoxes, and basic inference problems such as the subsumption and the instance problem. The course introduces techniques for solving these problems based on tableau-algorithms, automata, and other approaches. Also, the complexity of standard DLs is analyzed, identifying expressive DLs for which reasoning is expensive in the worst case, but still manageable in practice, and lightweight DLs for which reasoning is tractable.


The lecture takes place twice a week in room E05: Tuesday 16:40-18:10 (DS6) and Thursday 16:40-18:10 (DS6).

Lecture Material

A script of the lecture is not available and students are strongly recommended to copy what is written on the blackboard.

However, for the frog example we provide the slides:

and for the course example now really, really also:


From April 8th on, the exercise group takes place every Wednesday 16:40-18:10 (DS6), Room E05, and is held by Anni-Yasmin Turhan or Rafael Peñaloza.

Every week, an exercise sheet is made available for download from this webpage.

Credits / Examinations

Computational logic students can earn 9 credits by attending this lecture. The lecture can be used for the modules KRAI, IT, TCSL. In order to get the credits, CL students have to meet both of the following two obligations:
  1. present at least four exercises in front of the exercise group;

  2. pass an oral examination at the end of the term.
Computer Science students are not obliged to present exercises, but are invited to do so.


Anni-Yasmin Turhan