Deontic Dynamic Logic: a Retrospective

Abstract

In this paper a retrospective is given on the development of deontic dynamic logic. It first reviews the basic system PDeL as introduced in 1988, with emphasis on conceptual issues and technical choices and properties. It then continues with later developments and applications by ourselves and related work by others. Thus we will see how contrary-to-duties and free choice permissions are treated, and how violations can be handled more expressively, including a way of dealing with red/green states and transitions.