Knowledge Representation and Reasoning

Welcome to the newly established group headed by Johannes (P.) Wallner, specializing on Knowledge Representation & Reasoning (KRR).

If you are interested in student topics (e.g., for a Bachelor's or Master's thesis) you can have look at the topics page. A Bachelor's or Master's thesis can be started anytime (contact).

Broadly construed, knowledge representation & reasoning in Artificial Intelligence is concerned with foundational research questions such as how to represent knowledge and how to reason based on knowledge. Our research and teaching focuses on

  • formal studies of prominent logic-based representations of knowledge, and
  • addressing challenging computational reasoning tasks arising in KRR.

Our research agenda is to further understanding of complex forms of reasoning in knowledge representation, and to bring promising approaches closer to application, by going from theory to practice.

One of our main current areas is computational argumentation. For a general introduction to the topic, you can have a look, e.g., at the Handbook of Formal Argumentation or this article

** News **: Call for applications to the Doctoral Consortium (DC) of KR'24.

** New course **: Logic-based Knowledge Representation (winter term).

Below you find recent news (news archive).

Recent News

Doctoral Consortium at KR 2024


We are co-organizing this year's edition of the Doctoral Consortium (DC) of the prominent International Conference on Principles of Knowledge Representation and Reasoning (KR'24). The DC is a student mentoring program bringing together PhD students and senior researchers from the area of KR. 

The call for applications is available at the KR'24 webpage

Extended abstract accepted to AAMAS'24


Our work on "Abstracting Assumptions in Structured Argumentation" will be presented at this year's edition of AAMAS, and an extended abstract of our work will be published in the proceedings of this conference. In this work we look at possibilities of simplifying - abstracting - argumentation scenarios in the prominent structured argumentation formalisms of assumption-based argumentation (ABA).

Workshop in Vienna


We are co-organizing a workshop with TU Wien on "Recent Advances in Collaborative and Argumentative Decision-Making". The workshop will take place at TU Wien on November 24th.

Research on supporting decision-making is central to classical and modern Artificial Intelligence. Decision-making with several parties plausibly often involves both collaborative aspects and consensus regarding diverging opinions and conflicts. Two major research strands in these directions are Social Choice Theory and Formal Argumentation. The former is concerned, e.g., with collective decision making such as voting, while the latter aims to provide rational conclusions under inconsistent information.

The aim of this workshop is to bring together researchers from several parts of the diverse fields of Computational Social Choice and Formal Argumentation, in order to discuss recent results and ongoing work on the new challenges.

The programme can be found at the website of the workshop.

Participation in Competition


Our group participated in the recent 5th International Competition on Computational Models of Argumentation (ICCMA). In this competition solvers for computationally complex reasoning tasks in argumentation are evaluated against each other in terms of runtime efficiency.

Our group participated in two tracks: the dynamic track and the ABA track, with the former focusing on dynamically changing argumentation scenarios and the latter incorporating structural aspects of arguments. We contributed to the following submissions:

  • k-Solutions, developed by Christian Pasero,
  • ASTRA, developed by Andrei Popescu,
  • AcbAr, developed by Tuomo Lehtonen, and 
  • ASPforABA, developed by Tuomo Lehtonen.

These approaches each present their own algorithmic approach to computationally complex reasoning tasks. ASPforABA scored the first place where it participated. The results were presented in this year's International Conference on Principles of Knowledge Representation and Reasoning (KR2023) in Rhodes. Detailed results can be found here.

We thank the developers, contributors, and the competition organizers for the invaluable work for the scientific community!

Paper accepted to FCR'23


Our work on "Ranking-based Semantics for Assumption-based Argumentation" was accepted to the 9th Workshop on Formal and Cognitive Reasoning (FCR'23), a workshop at the German KI conference in 2023. 

In this work we look at ways of defining ranking-based semantics on the knowledge representation formalism assumption-based argumentation (ABA). Our ranking-based semantics relate assumptions, and we present ways of obtaining such semantics from existing ranking-based semantics on abstract argumentation. We define principles, i.e., properties of interest, ranking-based semantics on ABA may satisfy. 

Participation in AI Summer School 2023


Our group participated in the AI Summer School 2023, organized by the Austrian Society for Artificial Intelligence (ASAI) in Vienna. The pogramme included aspects of machine learning, knowledge graphs, declarative problem solving, and ethics in AI.