Polarized process algebra with reactive composition

Polarized processes are introduced to model the asymmetric interaction of systems. The asymmetry stems from the distinction between service and request. The scheduled concurrent composition of two polarized processes is called client-server composition or reactive composition, placing one process in the role of a client and the other process in the role of a server which is supposed to react on requests. The technical goal of this paper is to provide a definition of reactive composition for polarized processes and to prove that reactive composition thus defined is associative.