This seminar will be an introduction to epistemic logic and dynamic epistemic logic, the logics of knowledge, belief and change, with a focus on two specific aspects of these logics. First, I will briefly introduce epistemic logic. In this logic, some axioms dealing with the notion of knowledge are rather intricate and difficult to interpret intuitively, even though some of them, such as the axioms ".2" and ".3", are considered to be key axioms by some epistemic logicians. I will show that they can be characterized in terms of understandable interaction axioms relating knowledge and belief or knowledge and conditional belief. Second, I will briefly introduce dynamic epistemic logic, an extension of epistemic logic dealing with knowledge and information change. I will show how dynamic epistemic logic can be used to plan events in order to reach a specific epistemic situation, starting from a given epistemic situation.
The slides will be in English but the talk will be in French.