A Compositional Framework for Formally Verifying Modular Systems

We present a tool-supported framework for proving that the composition of the behaviors of the separate parts of a complex system ensures a desired global property of the overall system. A compositional inference rule is formally introduced and encoded in the logic of the PVS theorem prover. Methodological considerations on the usage of the inference rule are presented, and the framework is then used to prove a meaningful property of a simple, but significant, control system.