Thoughts about Incomplete Satis ability Procedures
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چکیده
Recent successes with incomplete satis ability procedures raise numerous issues about their uses and evaluation. Most such procedures search for \yes" answers, and give up if they do not nd one. The need for \no" answers as well is addressed. It is shown that a recent approximation algorithm of Yannakakis can produce \no" answers only in somewhat trivial cases. The possibility of salvaging information from a \yes" program that is giving up, and using it to nd a \no" answer is discussed. Two incomplete procedures were studied experimentally. One (based on \easy" resolutions) produces \no" answers. The other (based on Johnson's maximum satis ability approximation algorithm) produces \yes" answers. Both are deterministic, polynomial time algorithms, quadratic with careful implementation. Combined, they solved 83% of the formulas generated from a circuit-based application, ranging from 400 to over 10000 variables.
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تاریخ انتشار 1993