Knowledge Representation and Reasoning

Site under construction - preliminary page

Welcome to the newly established group headed by Johannes (P.) Wallner, specializing on Knowledge Representation & Reasoning (KRR). We are currently hiring to start our group at TU Graz.

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 (or related) 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

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

Below you find recent news (news archive).

Recent News


Fourth International Workshop on Systems and Algorithms for Formal Argumentation

We (co-)organized the fourth International Workshop on Systems and Algorithms for Formal Argumentation, dubbed SAFA, in Cardiff 2022 (September 13th). See also the webpage of the workshop.


New Course: Logic-based Knowledge Representation

We are offering a new course "Logic-based Knowledge Representation" for the first time this winter term. 

In this course we look at prominent logic-based approaches in knowledge representation and reasoning, with a focus on modeling, expressivity, and complexity of reasoning in these approaches. We look at (fragments of) classical logic, non-classical logic, and non-monotonic reasoning.

This course is part of several elective catalogues.

Registration and information can be found in TU Graz Online.


IJCAI organization

We supported the organization of IJCAI-ECAI 2022, this year in Vienna. 

Here we can see location of the conference banquet.


Two papers and a demo accepted to COMMA

Our works "Strongly Accepting Subframeworks: Connecting Abstract and Structured Argumentation" and "Algorithms for Reasoning in a Default Logic Instantiation of Assumption-Based Argumentation" were accepted to COMMA'22, a conference specialized to computational argumentation in AI. Moreover, a system demo associated to our recent paper to be presented at LPNMR'22 was accepted.

In the first work we look at possiblities of extending and generalizing recent research on strongly accepting subframeworks to more general structured argumentation frameworks, in particular assumption-based argumentation. We investigate conditions under which a generalization is possible.

In the second work we consider algorithmic approaches to a default logic instantiation of assumption-based argumentation, paving the way in particular for more expressive frameworks than were focused on before in terms of system implementations.  


Papers accepted to LPNMR'22 and NMR'22

Our work on "Representing Abstract Dialectical Frameworks with Binary Decision Diagrams" was accepted to LPNMR'22 and our work on "Argumentation Frameworks induced by Assumption-based Argumentation: Relating Size and Complexity" was accepted to the NMR'22 workshop. 

In the first work we investigate possibilities to utilize binary decision diagrams (BDDs) to reasoning in abstract dialectical frameworks (ADFs), a formal approach to argumentative reasoning. We show that complexity of reasoning can be milder, but not necessarily in polynomial-time, when using BDDs for ADFs. Based on the computational advantage of BDDs we apply a recently proposed framework of faceted navigation to develop heuristics for reasoning in ADFs. Preliminary experiments show potential advantage of this approach.

In the second work we look at the formal argument generation process that is prominent in computational argumentation. We show complexity results of argument generation, number of resulting argument structures, and that there is an apparent trade-off between number and complexity of resulting argument structures.


Talk at NAVAS workshop 2022 in Vienna

We will give a talk about our recent work on "Existential Abstraction on Argumentation Frameworks via Clustering" in the upcoming NAVAS workshop 2022 in Vienna. This workshop is organized by research groups at TU Wien and TU Dresden.