- Signal Transition Graphs (STG) are a formalism for the description of asynchronous circuit behaviour. In this paper we propose (and justify) a formal semantics of non-deterministic STGs with dummies. For this, we introduce a concept of output-determinacy, which is a relaxation of determinism, and argue that it is reasonable and useful in the speed-independent context. We apply the developed theory to justification of a new STG decomposition algorithm used to tackle the state explosion problem during circuit synthesis.
