BDD Based Procedures for a Theory of Equality with Uninterpreted Functions

The logic of equality with uninterpreted functions has been proposed for verifying abstract hardware designs. The ability to perform fast satisfiability checking over this logic is imperative for such verification paradigms to be successful. We present symbolic methods for satisfiability checking for this logic. The first procedure is based on restricting analysis to finite instantiations of the variables. The second procedure directly reasons about equality by introducing Boolean-valued indicator variables for equality. Theoretical and experimental evidence shows the superiority of the second approach.