Modular specification in rewriting logic (extended version)

Our aim is to bring modularity to system specification in rewriting logic. Modularity here is in the sense of decomposing a system into its functional components, coding the specification for each component as a separate system, and then assembling them back. Rewriting logic is well suited for the specification of concurrent and non-deterministic systems but, up to now, modularity could hardly be addressed within it. The base of our proposal is the operation that we call synchronous composition. We discuss the reasons and implications of our proposal, and formalize it for rewriting logic and also for transition structures, to be used as semantics. To show the power of our approach, we include a few small but realistic examples and a larger example on cached computer architecture.