Executable Speci cations for Concurrent Programming

Concurrent programming has been diicult to do, both from a programming and a formal ver-iication perspective. The main reasons are that the concurrency constructs are low-level and their use is intertwined with the rest of the program. In this paper, we use as a basis a new concurrent programming model called Open Constraint Programming. Its roots are in Concurrent Constraint Programming where there is a shared constraint store, and synchronization is achieved via constraint entailment. The key advantages here are (a) the concurrent behavior of agents is formalized and explicitly represented as constraints, (b) the speciication is executable, that is, agents run only as permitted, (c) there is a clear separation of the concurrent aspects of the agents' behavior from the rest of the code, and (d) agents are programming language independent.