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Title
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Exact algorithms for exact satisfiability and number of perfect matchings
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Author/s
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Andreas Björklund, Thore Husfeldt
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Department/s
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Department of Computer Science
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Full-text
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Full text is not available in this archive
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Alternative location (URL)
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http://dx.doi.org/10.1007/s004...
Restricted Access (Alternative Location)
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Publication/Series
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Algoritmica
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Publishing year
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2008
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Volume
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52
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Issue
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2
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Pages
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226 - 249
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Document type
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Journal article
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Status
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published
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Quality controlled
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yes
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Language
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English
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Publisher
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Springer
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Abstract
English
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We present exact algorithms with exponential running times for variants of n-element set cover problems, based on divide-and-conquer and on inclusion exclusion characterizations. We show that the Exact Satisfiability problem of size l with m clauses can be solved in time 2(m)l(O(1)) and polynomial space. The same bounds hold for counting the number of solutions. As a special case, we can count the number of perfect matchings in an n-vertex graph in time 2(n)n(O(1)) and polynomial space. We also show how to count the number of perfect matchings in time O(1.732(n)) and exponential space. We give a number of examples where the running time can be further improved if the hypergraph corresponding to the set cover instance has low pathwidth. This yields exponential-time algorithms for counting k-dimensional matchings, Exact Uniform Set Cover, Clique Partition, and Minimum Dominating Set in graphs of degree at most three. We extend the analysis to a number of related problems such as TSP and Chromatic Number.
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Subject
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Technology and Engineering
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Keywords
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set partition,
exact algorithms,
exact satisfability,
number,
of perfect matchings,
set cover
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ISBN/ISSN/Other
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ISSN: 0178-4617
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Research group
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Algorithms
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Project
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Exact algorithms
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Funder
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VR
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