Decidability Problems for Actor Systems

We introduce a nominal actor-based language and study its expressive power. We have identified the presence/absence of fields as a relevant feature: the dynamic creation of names in combination with fields gives rise to Turing completeness. On the other hand, restricting to stateless actors gives rise to systems for which properties such as termination are decidable. Such decidability result holds in actors with states when the number of actors is finite and the state is read-only.