An alternative logic for knowability

Abstract

We give an alternative logic for knowability to arbitrary public announcement logic. In the new semantics, 'knowable' means 'known after an information update' rather than the more specific interpretation of 'known after an announcement'. An update is modelled by the refining of accessibility relations. We compare our logic to arbitrary announcement logic and subset space logic and thus establish a link between the latter two. © 2011 Springer-Verlag.