Relating Fairness and Timing in Process Algebras

This paper contrasts two important features of parallel system computations: fairness and timing. The study is carried out at specification system level by resorting to a well-known process description language. The language is extended with labels which allow to filter out those process executions that are not (weakly) fair (as in [5,6]), and with upper time bounds for the process activities (as in [2]). We show that fairness and timing are closely related. Two main results are stated. First, we show that each everlasting (or non-Zeno) timed process execution is fair. Second, we provide a characterization for fair executions of untimed processes in terms of timed process executions. This results in a finite representation of fair executions using regular expression