On the analysis of cooperation and antagonism in networks of communicating processes

We propose a new method for the analysis of cooperative and antagonistic properties of communicating finite state processes (FSPs). This algebraic technique is based on a composition operator and on the notion of possibility equivalence among FSPs. We demonstrate its utility by showing that potential blocking, termination, and lockout can be decided in polynomial time for loosely connected networks of tree FSPs. Potential blocking and termination are examples of cooperative properties, while lockout is an antagonistic one. For loosely connected networks of (the more general) acyclic FSPs, the cooperative properties become NP-complete and the antagonistic ones PSPACE-complete. For tightly coupled networks of tree FSPs, we also have NP-completeness for the cooperative properties. For the harder case of FSPs with cycles, we provide a natural extension of the method.A preliminary version of this paper appeared as an extended abstract in theProceedings of the Fourth Annual ACM Symposium on Principles of Distributed Computing, August, 1985, pp. 23–38. P. C. Kanellakis was supported by ONR-DARPA Grant N00014-83-K-0146, NSF Grant DCR-8302391, and by the Office of Army Research under contract DAAG29-84-K-0058. S. A. Smolka was supported by National Science Foundation Grant DCR-8505873.