ACKNOWLEDGMENT

though the proposed method is sound, it is not a complete method, i.e., there are pairs of equivalent circuits for which it cannot prove equivalence. The method can be used as an effective preprocessing step for a general method such as [10]. It is interesting to note that for some synthesis steps, the method is complete. This is, e.g., the case for circuits optimized with combinational synthesis techniques, and also for retimed circuits. The proposed method assumes that an initial state is designated for both circuits. This initial state is used in two ways: It acts as a reference point to allow the detection of antivalent signals, and it is used to calculate the initial partition „H of the set p. The approach of [4] shows that the assumption of a designated initial state can be weakened. It should be possible to extend their work such that it also applies to the method presented in this paper