This ACG consists of two parts. I use the first hour of the colloquim as a tryout for a presentation which I will give in two weeks in Luxembourg, and I use the second hour to discuss the relation between Reo and non-monotonic reasoning.

Part 1: From input/output logic to normative multiagent systems

Normative multi-agent systems consist of sets of agents (human or artificial) whose interactions can fruitfully be regarded as norm-governed; the norms prescribe how the agents ideally should and should not behave. Examples are electronic commerce systems, legal systems, security systems, and so on. In this presentation I discuss requirements for (extensions of) input/output logics to be used in such systems.

Part 2: Reo and non-monotonicity

Exceptions have mostly been ignored in channel theory. In the logic of information flow (Barwise, Gabbay and Hartomas 1997) exceptions are not considered at all, and in the corresponding book (Barwise and Seligman, 1997) exceptions are modelled by replacing channels by other more refined channels. In Reo, exceptions in lossy channels and prioritized mergers play an important role in many examples. To discuss the relation between Reo and non-monotonic logic I consider a simple fragment of Reo that does not consider reconfiguration, that considers only synchronous channels, and that contains only one value. Flow or no flow, that's the question in this language.