An Algebra of Actors

In this paper, we introduce an actor language following a ``process algebra'' style. The idea is to define a formalism that enjoys a clean formal definition allowing the reuse of standard results of the theory of concurrency in a context where an high level object oriented programming style is preserved. We provide an operational semantics based on a labelled transition system which allows us to discuss how different notions of equivalence, such as standard and asynchronous bisimulation, map in the actor model. To illustrate the expressive power of the language, we provide an encoding of the asynchronous $\pi$-calculus and several programming examples. Finally, we define a simple object oriented notation and we provide a specification of the Hurried Philosophers case study