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Title Exact algorithms for exact satisfiability and number of perfect matchings
Author/s Andreas Björklund, Thore Husfeldt
Department/s Department of Computer Science
Full-text Full text is not available in this archive
Alternative location (URL) http://dx.doi.org/10.1007/s004... Restricted Access (Alternative Location)
Publication/Series Algoritmica
Publishing year 2008
Volume 52
Issue 2
Pages 226 - 249
Document type Journal article
Status published
Quality controlled yes
Language English
Publisher Springer
Abstract English 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.
Subject Technology and Engineering
Keywords set partition, exact algorithms, exact satisfability, number, of perfect matchings, set cover
ISBN/ISSN/Other ISSN: 0178-4617
Research group Algorithms
Project Exact algorithms
Funder VR

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