Towards an Algebra of Actors

We present a study of the interaction properties of objects in concurrent object oriented programming. We identify a set of basic interaction mechanisms: object identity, asynchronous message passing, implicit receive primitive, which are closed to those of the actor model. Then, we define a minimal algebra of actors as a basic formalism for representing the semantics of concurrent object oriented programming. Finally, we define a notion of observation equivalence between the actor terms of the algebra which has been proved to be a congruence with respect to the parallel composition operator. 1. This paper has been partially supported by the Italian Ministry of Universities (MURST) and by the ESPRIT BRA Project 9102Coordination. 2. Dipartimento di Scienze dell’Informazione, University of Bologna, Piazza Porta S. Donato 5, 40127 Bologna, Italy. E-mail: [email protected]