A Folding Strategy for SAT solvers based on Shannon's expansion theorem

SAT problem has been an active research subject and many impressive SAT solvers have been proposed. Most of algorithms used in modern SAT solvers are based on tree structured searching strategy, combining with heuristic approaches to reduce the search space. In contrast to most existing solvers, we treat SAT problem as a logical optimization issue which can be solved by a logic minimizer. In this paper, we propose a Folding Strategy (FS) based on the Shannon's expansion theorem such that in every step, one variable is deducted and the size of search space is shrunk. The new method will find the solution after Karnaugh Map (K-Map) is folded no more than n (number of variables) times because search space is decreased by half in each folding step.