A correctness criterion for asynchronous circuit validation and optimization

We propose a new relation C. called strong conformance in the context of Dill's trace theory, and define B Q A to be true exactly when B conforms to A and the success set of B contains the success set of A. When B C. A, module B operated in module A's maximal environment AM (i.e. B || AM) exhibits all the traces that A \\ AM exhibits. In addition, if A has a success trace x, B can have additional success traces of the form xi?* where i is an input and a is the alphabet of the trace structure. This means that B can have additional capabilities that A does not. We show that strong conformance is more useful than conformance (defined by Dill) in detecting certain errors in asynchronous circuits. Strong conformance also helps justify circuit optimization rules that replace a component A by another component B that may have extra capabilities (e.g. can accept more inputs). The structural operators compose, rename, and hide of Dill's trace theory are monotonic with respect to strong conformance. Experiments using a modified version of Dill's trace theory verifier are presented.