Verification Architectures: Compositional Reasoning for Real-time Systems
Abstract
We introduce a conceptual approach to decompose real-time systems, specified by integrated formalisms: instead of showing safety of a system directly, one proves that it is an instance of a Verification Architecture, a safe behavioural protocol with unknowns and local realtime assumptions. We examine how different verification techniques can be combined in a uniform framework to reason about protocols, assumptions, and instantiations of protocols. The protocols are specified in CSP, extended by data and unknown processes with local assumptions in a real-time logic. To prove desired properties, the CSP dialect is embedded into dynamic logic and a sequent calculus is presented. Further, we analyse the instantiation of protocols by combined specifications, here illustrated by CSP-OZ-DC. Using an example, we show that this approach helps us verify specifications that are too complex for direct verification.