Tight integration of combinational verification methods

Combinational verification is an important piece of most equivalence checking tools. In the recent past, many combinational verification algorithms have appeared in the literature. Previous results show that these algorithms are able to exploit circuit similarity to successfully verify large designs. However, none of these strategies seems to work when the two input designs are not equivalent. We present our combinational verification algorithm, with evidence, that is designed to be robust for both the positive and the negative problem instances. We also show that a tight integration of different verification techniques, as opposed to a coarse integration of different algorithm, is more effective at solving hard instances.