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http://hdl.handle.net/10012/4810
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| Title: | Backdoors in Satisfiability Problems |
| Authors: | Li, Zijie |
| Keywords: | CSP
SAT
Backdoors |
| Approved Date: | 8-Oct-2009 |
| Date Submitted: | 2009 |
| Abstract: | Although satisfiability problems (SAT) are NP-complete, state-of-the-art SAT solvers are able to solve large practical instances. The notion of backdoors has been introduced to capture structural properties of instances. Backdoors are a set of variables for which there exists some value assignment that leads to a polynomial-time solvable sub-problem. I address in this thesis the problem of finding all minimal backdoors, which is essential for studying value and variable ordering mistakes. I discuss our definition of sub-solvers and propose algorithms for finding backdoors. I implement our proposed algorithms by modifying a state-of-the-art SAT solver, Minisat. I analyze experimental results comparing our proposed algorithms to previous algorithms applied to random 3SAT, structured, and real-world instances. Our proposed algorithms improve over previous algorithms for finding backdoors in two ways. First, our algorithms often find smaller backdoors. Second, our algorithms often find a much larger number of backdoors. |
| Program: | Computer Science |
| Department: | School of Computer Science |
| Degree: | Master of Mathematics |
| URI: | http://hdl.handle.net/10012/4810 |
| Appears in Collections: | Electronic Theses and Dissertations (UW)
Faculty of Mathematics Theses and Dissertations
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