Belief change and non-monotonic reasoning are usually viewed as two sides of the same coin, with results showing that one can formally be defined in terms of the other. In this talk we will discuss that it also makes sense to analyse belief change within a non-monotonic framework, and in particular we take under consideration a preferential non-monotonic framework. We consider belief change operators in a non-monotonic propositional setting with a view towards preserving consistency. We show that the results obtained can also be applied to the preservation of coherence - an important notion within the field of logic-based ontologies. We adopt the AGM approach to belief change and show that standard AGM can be adapted to a preferential non-monotonic framework, with the definition of expansion, contraction, and revision operators, and corresponding representation results.

Brief bio: Tommie Meyer is a full professor in the Department of Computer Science at UCT, the UCT-CSIR Chair in Artificial Intelligence, and Director of the Centre for Artificial Intelligence Research (CAIR) at the CSIR in South Africa. Prior to this he was a chief scientist at the CSIR, a senior researcher at NICTA in Australia, conjoint associate professor at the University of New South Wales in Australia, associate professor at the University of Pretoria, and senior lecturer at the University of South Africa. He is recognised internationally as an expert in Knowledge Representation and Reasoning. He is a member of the steering committee of the International Conference on Principles of Knowledge Representation (KR), chair of the steering committee of the Nonmonotonic Reasoning workshop series, associate editor of the journal Artificial Intelligence, and editorial board member of the Journal of Artificial Intelligence Research. He has published in all the top journals and conferences in Artificial Intelligence.