Encapsulating Concurrency as an Approach to Unification

We extend traditional techniques for sequential specification and verification to systems involving intrinsically concurrent activities. Our approach uses careful design of component specifications to encapsulate inherent concurrency, and hence isolate clients from associated verification concerns. The approach has three parts: (i) relational specifications to capture the interleaved effects of concurrent threads of execution, (ii) intermediate components to support a client’s view of being the only active thread of computation, and (iii) a new specification clause to express requirements on a client’s future behavior. We illustrate these ideas, and discuss their merits, in the context of a case study specified using RESOLVE.