Parallel Composition of Assumption-commitment Speciications a Unifying Approach for Shared Variable and Distributed Message Passing Concurrency

We unify the parallel composition rule of assumption-commitment speciications for respectively state-based and message-based concurrent processes. Without providing language-dependent deenitions, we rst assume that the model of a process can be given as a set of`sequences' (e.g., traces, state sequences). Then we assume the existence of a merging operator that captures the compositionality of that model. On this basis, we formulate a semantic parallel composition rule for assumption-commitment speciications wherein the merging operator behaves as a parameter. Then, by providing suitable language-speciic deenitions for the model of a process and the merging operator, we transform the semantic rule into syntactic ones, both for the state-based and message-based approaches to concurrency.