Composing and Refining Dense Temporal Logic Specifications

A dense temporal logic development method for the specification, refinement, composition and verification of reactive systems is introduced. A reactive system is specified by a pair consisting of a machine and a condition that indicate the valid computations of this machine. Compositionality is achieved by indicating whether each step is an environment step, a system step, or a communication step. Refinement can be expressed straightforwardly in the logic because the stutter problem is elegantly solved by using the dense structure of the logic. Compositionality enables us to break refinement between complex systems into refinement between small and simple systems. The latter can then be verified by existing proof rules for refinement which are reformulated in our formalism. Received January 1997 / Accepted in revised form April 2000