Abstract

A distributed computer system consists of different processes or agents that function largely autonomously and coordinate their actions by communicating with each other. In such a situation, actions may be performed by different agents of the system locally, in a concurrent manner. In this paper, we first discuss formal models of distributed systems in which concurrency is specified explicitly, in contrast to more traditional approaches where concurrency is represented implicitly as a non-deterministic choice between all possible sequentializations of concurrent actions. This naturally leads to models based on partially-ordered sets of actions rather than sequences of actions and is often called the true concurrency approach. The models we focus on are distributed transition systems, elementary net systems and event structures. In the second half of the paper, we develop a family of logics to specify and reason about the behavioural properties of the models we have described. The logic...

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