A compositional rule for hardware design refinement

We present an approach to designing verified digital systems by a sequence of small local refinements. Refinements in this approach are not limited to a library of predefined transformations for which theorems have been previously established. Rather, the approach relies on localizing the refinement steps in such a way that they can be verified efficiently by model checking. Toward this end, a compositional rule is proposed by which each design refinement may be verified independently, in an abstract environment. This rule supports the use of downward refinement maps, which translate abstract behavior detailed behavior. These maps may involve temporal transformations, including delay. The approach is supported by a verification tool based on symbolic model checking.