Foreword

Following initial benchmarks like Jan Plaza’s public announcement logic (Plaza, 1989), Johan van Benthem’s dynamic modal setting of AGM theory revision (van Benthem, 1989), and Gerbrandy and Groeneveld’s mix of dynamic update operators and epistemic operators (Gerbrandy et al., 1997), logics mixing epistemic and dynamic logic became more and more popular. They have been studied under the denomination dynamic epistemic logics (DEL). One of the parameters of dynamic epistemic logics is the kind of epistemic operator that is considered, ranging from individual to common knowledge, and another parameter is the kind of change that can be modelled, ranging from public to private events.