The MaxSAT problem and some of its well-known variants find an increasing number of practical applications in a wide range of areas. Examples include different optimization problems in system design and verification. However, most MaxSAT problem instances from these practical applications are too hard for existing branch and bound algorithms. One recent alternative to branch and bound MaxSAT algorithms is based on unsatisfiable subformula identification. A number of different unsatisfiability-based MaxSAT algorithms have been developed, which are effective at solving different classes of problem instances. All MaxSAT algorithms based on unsatisfiable subformula identification require using additional Boolean variables, either to allow relaxing some of the clauses or to encode cardinality constraints used by these algorithms. As a result, these algorithms may require using a significant number of additional Boolean variables, that can exceed the original number of variables for some problem instances. This paper proposes techniques for effectively reducing the number of auxiliary variables that must be used in unsatisfiability-based MaxSAT algorithms. Experimental results indicate that the techniques for reducing the number of auxiliary variables are effective, and contribute to more efficient MaxSAT algorithms.
[1]
Felip Manyà,et al.
New Inference Rules for Max-SAT
,
2007,
J. Artif. Intell. Res..
[2]
Sean Safarpour,et al.
Improved Design Debugging Using Maximum Satisfiability
,
2007
.
[3]
Joao Marques-Silva,et al.
Algorithms for Maximum Satisfiability using Unsatisfiable Cores
,
2008,
2008 Design, Automation and Test in Europe.
[4]
Niklas Sörensson,et al.
An Extensible SAT-solver
,
2003,
SAT.
[5]
Albert Oliveras,et al.
MiniMaxSat: A New Weighted Max-SAT Solver
,
2007,
SAT.
[6]
Joao Marques-Silva,et al.
On Using Unsatisfiability for Solving Maximum Satisfiability
,
2007,
ArXiv.
[7]
Niklas Sörensson,et al.
Translating Pseudo-Boolean Constraints into SAT
,
2006,
J. Satisf. Boolean Model. Comput..
[8]
Sharad Malik,et al.
On Solving the Partial MAX-SAT Problem
,
2006,
SAT.
[9]
Steven David Prestwich,et al.
Variable Dependency in Local Search: Prevention Is Better Than Cure
,
2007,
SAT.
[10]
Sharad Malik,et al.
Validating SAT solvers using an independent resolution-based checker: practical implementations and other applications
,
2003,
2003 Design, Automation and Test in Europe Conference and Exhibition.