Refinement of Actions in Circus,

AbstractThis paper presents refinement laws to support the development of actions in Circus, a combination of Z and CSP adequate to specify the data structures and behavioural aspects of concurrent systems. In this language, systems are characterised as a set of processes; each process is a unit that encapsulates state and reactive behaviour defhed by actions. Previously, we have addressed the issue of refining processes. Here, we are concerned with the actions that compose the behaviour of such processes, and that may involve both Z and CSP constructs. We present a number of useful laws, and a case study that illustrates their application