A SAT Approach to Branchwidth

Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9710)


Branch decomposition is a prominent method for structurally decomposing a graph, hypergraph or CNF formula. The width of a branch decomposition provides a measure of how well the object is decomposed. For many applications it is crucial to compute a branch decomposition whose width is as small as possible. We propose a SAT approach to finding branch decompositions of small width. The core of our approach is an efficient SAT encoding which determines with a single SAT-call whether a given hypergraph admits a branch decomposition of certain width. For our encoding we developed a novel partition-based characterization of branch decomposition. The encoding size imposes a limit on the size of the given hypergraph. In order to break through this barrier and to scale the SAT approach to larger instances, we developed a new heuristic approach where the SAT encoding is used to locally improve a given candidate decomposition until a fixed-point is reached. This new method scales now to instances with several thousands of vertices and edges.


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Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  • Neha Lodha
    • 1
  • Sebastian Ordyniak
    • 1
  • Stefan Szeider
    • 1
  1. 1.Algorithms and Complexity GroupTU WienViennaAustria

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