Simplifying Clausal Satis ability Problems?

Recently linear 0-1 programming methods have been successfully applied to the satissability problem of propositional logic. We present a preprocessing method that simpliies the linear 0-1 integer problem corresponding to a clausal satissability problem. Valid extended clauses, a generalization of classical clauses, are added to the problem as long as they dominate at least one extended clause of the problem. We describe how to eeciently obtain these valid extended clauses and apply the method to some combinatorial satissability problems. The reformu-lated 0-1 problems contain less but usually stronger 0-1 inequalities and are typically solved much faster than the original one with traditional 0-1 integer programming methods.