Non-Deterministic Graph Searching: From Pathwidth to Treewidth

Abstract : We introduce nondeterministic graph searching with a controlled amount of nondeterminism and show how this new tool can be used in algorithm design and combinatorial analysis applying to both pathwidth and treewidth. We prove equivalence between this game-theoretic approach and graph decompositions called q -branched tree decompositions, which can be interpreted as a parameterized version of tree decompositions. Path decomposition and (standard) tree decomposition are two extreme cases of q-branched tree decompositions. The equivalence between nondeterministic graph searching and q-branched tree decomposition enables us to design an exact (exponential time) algorithm computing q-branched treewidth for all q≥0, which is thus valid for both treewidth and pathwidth. This algorithm performs as fast as the best known exact algorithm for pathwidth. Conversely, this equivalence also enables us to design a lower bound on the amount of nondeterminism required to search a graph with the minimum number of searchers.
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Article dans une revue
Algorithmica, Springer Verlag, 2009, 53 (3), pp.358-373. <10.1007/s00453-007-9041-6>
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Contributeur : Nicolas Nisse <>
Soumis le : vendredi 2 octobre 2009 - 01:25:33
Dernière modification le : mercredi 12 octobre 2016 - 01:23:17




Fedor Fomin, Pierre Fraigniaud, Nicolas Nisse. Non-Deterministic Graph Searching: From Pathwidth to Treewidth. Algorithmica, Springer Verlag, 2009, 53 (3), pp.358-373. <10.1007/s00453-007-9041-6>. <hal-00421417>



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