Quantifying over information change

Hans van Ditmarsch (LORIA – CNRS / University of Lorraine, France) and Louwe B. Kuijer (University of Liverpool, United Kingdom)

In dynamic epistemic logics, also known as update logics, a modality that is interpreted as a model transformer represents information change. Examples are public announcement logic, action model logic, and arrow update logic. Such logics can be expanded with operators describing quantification over information change to represent, for example, ‘there is an announcement after which formula phi is true’ (where phi is some postcondition in the resulting structure), or ‘there is an action model after which phi is true’. Over the past 10 to 15 years several such logics with propositional quantification have been proposed. They are indispensible in describing epistemic planning problems. We will present various such logics in depth, including around the general themes expressivity, axiomatization, decidability, quantifying over world/relation/factual change, and we will also present related logics such as sabotage logic.