A Formal Model of Concurrency for Distributed Object-Oriented Systems

It is widely accepted that object-oriented constructions can be used as a pertinent basis for the support of distributed systems consisting of concurrently executing objects that communicate and interoperate among them. In this context, distributed object systems are representedfrom a process-oriented perspective which uses the process as the basic modelling structure. This point of view allows us to model concurrent objects as a collection of interacting processes, each of them describing a pattern of behaviour This paper aims to provide a formal foundation for objectoriented constructions. To do so, we present a formal model of concurrent objects based on a well-de$ned process theory, the x-calculus, which oglers a very effective mechanism of specification and verification. The election of the n-calculus is justified by some of itsfeatures---e.g., mobility and higher-order constructions- for they will be essential to the description of some object behaviour and constructions. 1