[TU Dresden]

Description Logics

Technische Universität Dresden
Institut für Theoretische Informatik
Lehrstuhl für Automatentheorie

Prof. Franz Baader


The lectures on 14th of June and 21st of June are cancelled. Thus the tutorial on the 15th of July is cancelled as well.

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 in room E05: Tuesday and Thursday always at 16:40-18:10 (DS6). In addition, some lectures will take place in room E05 on Monday 16:40-18:10 (DS6) as substitutes for lectures that cannot be held during the regular Tuesday/Thursday slot. The exact distribution of lectures and tutorials is displayed here:

  Monday Tuesday Wednesday Thursday Friday
12.4 - 16.4   Lecture Lecture Lecture  
19.4 - 23.4 Tutorial
Exercise sheet 1
Lecture Lecture Lecture  
26.4 - 30.4 Lecture Lecture Tutorial
Exercise sheet 2
03.5 - 07.5 Lecture Lecture   Lecture  
10.5 -14.5   Tutorial
Exercise sheet 3
Exercise sheet 4
17.5 - 21.5 Lecture Lecture Tutorial
Exercise sheet 5
24.5 - 28.5          
31.5 - 04.6 Lecture Lecture Tutorial
Exercise sheet 6
07.6 - 11.6 Lecture Tutorial
Exercise sheet 7
Lecture Lecture  
14.6 - 18.6 Lecture
Lecture Tutorial
Exercise sheet 8
21.6 - 25.6 Lecture
Lecture Tutorial
Exercise sheet 9
28.6 - 02.7     Tutorial
Exercise sheet 10
05.7 - 09.7     Tutorial
Exercise sheet 11
12.7 - 16.7     Tutorial
Exercise sheet 12 and 38) from sheet 11
19.7 - 23.7          


The first exercise takes place on Monday 19th of April 16:40-18:10 (DS6), Room E05. From April 21st on, the exercise group takes place every Wednesday 16:40-18:10 (DS6) in Room E05 by default. Exceptions are listed in the table above. The tutorial is held by Anni-Yasmin Turhan. Every week, an exercise sheet is made available for download from this webpage from the table above.

Lecture Material

A script of the lecture is not available and students are strongly recommended to copy what is written on the blackboard. We provide the slides for the introductory sessions: We also provide scanned versions of the example slides used in the session about frames and semantic networks:

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