Expressing Priorities and External Probabilities in Process Algebra via Mixed Open/Closed Systems

Defining operational semantics for a process algebra is often based either on labeled transition systems that account for interaction with a context or on the so-called reduction semantics: we assume to have a representation of the whole system and we compute unlabeled reduction transitions (leading to a distribution over states in the probabilistic case). In this paper we consider mixed models with states where the system is still open (towards interaction with a context) and states where the system is already closed. The idea is that (open) parts of a system "P" can be closed via an operator "P G" that turns already synchronized actions whose "handle" is specified inside "G" into prioritized reduction transitions (and, therefore, states performing them into closed states). We show that we can use the operator "P G" to express multi-level priorities and external probabilistic choices (by assigning weights to handles inside G), and t...

• Type: Journal
• Year: 2008
• Where: ENTCS
• Authors: Mario Bravetti
• Keywords: ENTCS 2008, Operational Semantics, Reduction Transitions, Transition System