  In this work a stand-alone preprocessor for SAT is presented that is able to
perform most of the known preprocessing techniques. Preprocessing a formula in
SAT is important for performance since redundancy can be removed. The
preprocessor is part of the SAT solver riss and is called Coprocessor. Not only
riss, but also MiniSat 2.2 benefit from it, because the SatELite preprocessor
of MiniSat does not implement recent techniques. By using more advanced
techniques, Coprocessor is able to reduce the redundancy in a formula further
and improves the overall solving performance.
