Description Logics (DLs) have a long tradition in computer science and knowledge representation, being designed so that domain knowledge can be described and so that computers can reason about this knowledge. DLs have recently gained increased importance since they form the logical basis of widely used ontology languages, in particular the web ontology language OWL. Starting from a basic DL, this course introduces the students to their syntax, semantics, reasoning problems and model theory, and discusses the computational complexity of these reasoning problems and algorithms to solve them.

### Course Description

### Organisation

The lecture is accompanied by weekly tutorials held by Dr. Stefan Borgwardt. The lectures and tutorials take place in room APB/E005 on

- Tuesdays 16:40–18:10,
- Wednesdays 14:50–16:20, and
- Thursdays 16:40–18:10.

The distribution of lectures and tutorials can be found in the table below. During the semester, there may be changes to this schedule on short notice. Be sure to check this page regularly for updates.

Exercise sheets will be made available on this page approximately one week before each tutorial. During the tutorials, the students can present and discuss their solutions to the exercises, and ask questions about description logics.

*Changes:*

- The lecture on Tuesday, 28 Nov, was swapped with the tutorial on Wednesday, 29 Nov.
- The lecture on Wednesday, 6 Dec, was swapped with the tutorial on Tuesday, 12 Dec.
- Exercise 8.5 was corrected.
*The lecture on Tuesday, 30 Jan, was replaced with a tutorial, and the lecture on Wednesday, 31 Jan, was swapped with the tutorial on Thursday, 1 Feb.*

Week | Tuesday | Wednesday | Thursday |
---|---|---|---|

9 Oct to 13 Oct |
Lecture | Lecture | Lecture |

16 Oct to 20 Oct |
Lecture | Tutorial (Exercise Sheet 1) |
Lecture |

23 Oct to 27 Oct |
Lecture | Tutorial (Exercise Sheet 2) |
Lecture |

30 Oct to 3 Nov |
Public holiday (Re |
Lecture + Tutorial |
Lecture |

6 Nov to 10 Nov |
Tutorial (Exercise Sheet 3) |
Tutorial (Exercise Sheet 4) |
Lecture |

13 Nov to 17 Nov |
Lecture | Tutorial (Exercise Sheet 5) |
Lecture |

20 Nov to 24 Nov |
Tutorial (Exercise Sheet 6) |
Public holiday (Buß- und Bettag) |
Lecture |

27 Nov to 1 Dec |
Tutorial (Exercise Sheet 7) |
Lecture | Lecture |

4 Dec to 8 Dec |
Lecture | Tutorial (Exercise Sheet 8) |
Lecture |

11 Dec to 15 Dec |
Lecture | Tutorial (Exercise Sheet 9) |
Lecture |

18 Dec to 22 Dec |
Lecture | Tutorial (Exercise Sheet 10) |
— |

25 Dec to 29 Dec |
— | — | — |

1 Jan to 5 Jan |
— | — | Lecture |

8 Jan to 12 Jan |
Lecture | Tutorial (Exercise Sheet 11) |
Lecture |

15 Jan to 19 Jan |
Lecture | Tutorial (Exercise Sheet 12) |
Lecture |

22 Jan to 26 Jan |
Lecture | Lecture | Tutorial (Exercise Sheet 13) |

29 Jan to 2 Feb |
Tutorial | Tutorial + Questions |
Lecture |

### SWS/Modules

*SWS:* 4/2/-

*Modules:*

- Bachelor Informatik: INF-B-510 (Vertiefung in der Informatik), INF-B-520 (Spezialisierung in der Informatik)
- Master Informatik, Diplom Informatik: INF-BAS6 (Theoretische Informatik), INF-VERT6 (Vertiefung Theoretische Informatik)
- Master Computational Logic, European Master in Computational Logic: MCL-TCSL / EMCL-A-TCSL (Theoretical Computer Science and Logic), MCL-PI / EMCL-A-PI (Principles of Inference), MCL-AI / EMCL-A-AI (Artificial Intelligence)

### Lecture Material

Students are strongly recommended to copy what is written on the blackboard. Slides are used for most of the lectures, except for the proofs:

### Literature

- Franz Baader, Carsten Lutz, Ian Horrocks, and Uli Sattler: An Introduction to Description Logic. Cambridge University Press, 2017.

Also available for download at the publisher's web page via SLUB Dresden (only from within the network of TU Dresden). - Franz Baader, Diego Calvanese, Deborah McGuinness, Daniele Nardi, and Peter F. Patel-Schneider: The Description Logic Handbook: Theory, Implementation, and Applications. Cambridge University Press, 2nd edition, 2007.
- Franz Baader, Carsten Lutz: Description Logic. In Patrick Blackburn, Johan van Benthem, and Frank Wolter, editors, Handbook of Modal Logic, pages 757–819. Elsevier, 2006.

doi:10.1016/S1570-2464(07)80016-4 - Franz Baader. Description Logics. In Reasoning Web: Semantic Technologies for Information Systems, 5th International Summer School 2009, volume 5689 of Lecture Notes in Computer Science, pages 1–39. Springer-Verlag, 2009.

doi:10.1007/978-3-642-03754-2_1