Epistemic logics for multi-agent systems by Hans van Ditmarsch

Epistemic logic models knowledge and belief in multi-agent systems. How to model change of knowledge has been investigated since the 1980s. Following the influential Interpreted Systems approach as presented in the textbook 'Reasoning about Knowledge' by Fagin et al. (1995), a strand of modal logic with epistemic modal operators for knowledge and dynamic modal operators for knowledge change has developed during the 1990s, based on initial contributions by Plaza (1989) and van Benthem (1987/1989). The action model approach proposed by Baltag, Moss, Solecki (1998) has been the most influential. The textbook 'Dynamic Epistemic Logic' (van Ditmarsch et al, 2007) gives an overview of these developments. The area has continued to develop strongly, for example also incorporating factual change, belief revision, and propositional quantification. In these two tutorial sessions I will give the basics of Dynamic Epistemic Logic, focussing on the semantics and on applications. The topics treated are: logic of knowledge, public announcements, action models, belief revision, factual change, the relation to temporal modal logic (paving the way for the next lecturer), and quantifying over information change.