Abstract

Resolution has not been an effective tool for deciding satisfiability of propositional CNF formulas, due to explosion of the search space, particularly when the formula is satisfiable. However, a new pruning method, which is designed to eliminate certain refutation attempts that cannot succeed, has been shown to eliminate much of the redundancy of propositional model elimination. The pruning method exploits the concept of "autarky", which was introduced by Monien and Speckenmeyer. Informally, an autarky is a "self-sufficient" model for some clauses, but which does not affect the remaining clauses of the formula. Autarky pruning permits the algorithm, called "Modoc", to be "two-sided" in the sense that it constructs a model if the formula is satisfiable and constructs a refutation proof if it is not. This talk describes new "lemma" and "cut" strategies that are efficient to apply in the setting of propositional resolution. It builds upon the C-literal strategy proposed by Shostak, and s...

Citations