Seminar Forgetting and Relevance SS 2016

Submitted by Christoph Schwering on 30. December 2015 - 20:59

In this seminar we will study concepts of forgetting and relevance developed in the field of Knowledge Representation. Humans not only forget unintentionally but also intentionally, for example, when they obtain new information and delete previous contradicting and apparently false information. In fact, humans usually do not forget irrevocably; we can bring back memories and reconstruct forgotten knowledge. In formal languages as studied in KR, however, even supposedly simple forgetting often turns out very difficult. In this seminar, we will study techniques for forgetting in KR languages such as predicate logic, description logics, or answer set programs. Related to forgetting is the concept of relevance among different facts. For example, when some fact is to be forgotten, this may also affect other facts relevant to the forgotten fact. Relevance is useful to develop tractable reasoning and handling inconsistencies in a knowledge base.


Students of Bachelor and Master programs can participate in this seminar. For Master Informatik students, the seminar belongs to the fields Theoretische Informatik and Daten- und Informationsmanagement. For Master Software Systems Engineering (SSE) students, it belongs to the fields Theoretical Foundations of SSE and Data and Information Management.

Places are allocated centrally from 14.01.2016 until 27.01.2016. In your application please clearly indicate your prior knowledge of the subject (see the requirements section). We won't be able to consider your application otherwise. The number of available slots is limited.


A thorough knowledge of logic and knowledge representation is absolutely essential. Relevant courses include the Mathematical Logic course from the Mathematical Foundations of Computer Science group and our lectures on Knowledge Representation and The Logic of Knowledge Bases.


  1. Second-Order Quantifier Elimination
    • Gabbay, Szalas: Second-Order Quantifier Elimination in Higher-Order Contexts with Applications to the Semantical Analysis of Conditionals pdf
  2. Forgetting in Proper+ Knowledge Bases
    • Lin, Reiter: Forget It! pdf
    • Liu, Lakemeyer: On First-Order Definability and Computability of Progression for Local-Effect Actions and Beyond pdf
  3. Necessary Sufficient Conditions
    • Doherty, Lukaszewicz, Szalas: Computing Strongest Necessary and Weakest Sufficient Conditions of First-Order Formulas pdf
    • Lin: On strongest necessary and weakest sufficient conditions pdf
  4. Forgetting in Description Logics and Logic Programs
    • Eiter, Ianni, Schindlauer, Tompits, Wang: Forgetting in Managing Rules and Ontologies pdf
    • Eiter, Wang: Semantic forgetting in answer set programming pdf
  5. Forgetting in Description Logics
    • Konev, Walther, Wolter: Forgetting and uniform interpolation in large-scale description logic terminologies pdf
    • Lutz, Wolter: Foundations for Uniform Interpolation and Forgetting in Expressive Description Logics pdf
    • Wang, Wang, Topor, Pan: Forgetting for Knowledge Bases in DL-Lite pdf
  6. Forgetting in Logic Programs
    • Zhang, Foo: Solving logic program conflict through strong and weak forgettings pdf
  7. Forgetting in Modal Logic
    • Zhang, Zhou: Knowledge forgetting: Properties and applications pdf
  8. Implicit and Explicit Relevance
    • Lakemeyer: All you ever wanted to know about Tweety pdf
    • Lakemeyer: Relevance from an epistemic perspective pdf
  9. Propositional Independence
    • Lang, Liberatore, Marquis: Propositional Independence pdf
  10. Logical Conditional Independence
    • Darwiche: A logical notion of conditional independence: properties and applications pdf
  11. Relevance in Belief Structures
    • Chopra, Parikh: Relevance sensitive belief structures pdf
  12. Relevance through Letter Sharing and Belief Change
    • Kourousias, Makinson: Parallel interpolation, splitting, and relevance in belief change pdf
    • Makinson: Propositional Relevance through Letter-Sharing pdf
  13. Reasoning under Inconsistency
    • Lang, Marquis: Reasoning under inconsistency: A forgetting-based approach pdf

Additional information

Introductory Meeting
The date and time for the introductory meeting will be announced here. Participation is compulsory.
Seminar Procedure
Besides writing your own term paper, you are asked to review other students' term papers. We will use a conference management system (e.g., EasyChair) for this procedure. It will involve strict deadlines. Meeting these deadlines is mandatory. At the end of the seminar each student needs to give a talk on his topic in front of the other students and members of our group. Attendance of these talks and participation in the discussions is mandatory.
Seminar Date
The seminar will be held as a block seminar on two or three days, likely during the semester break.
You may use this LaTeX template for your term paper.
General Info
The introductory slides contain information about the schedule and requirements.
Library Tour
Renate Eschenbach from the Computer Science Library offers guided tours on how to find literature in the library and how to prepare a seminar. Interested students should enlist for a tour in the preliminary discussion.