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    A 1.375-Approximation Algorithm for Sorting
    by Transpositions

    Isaac Elias and Tzvika Hartman

    Abstract

    Sorting permutations by transpositions is an important problem in genome rearrangements. A transposition is a rearrangement operation in which a segment is cut out of the permutation and pasted in a different location. The complexity of this problem is still open and it has been a ten-year-old open problem to improve the best known 1.5-approximation algorithm. In this paper we provide a 1.375-approximation algorithm for sorting by transpositions. The algorithm is based on a new upper bound on the diameter of 3-permutations. In addition, we present some new results regarding the transposition diameter: We improve the lower bound for the transposition diameter of the symmetric group, and determine the exact transposition diameter of 2-permutations and simple permutations.

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    In Proc. of the 5th International Workshop on Algorithms in Bioinformatics (WABI'05), volume 3692 of Lecture Notes in Computer Science, pages 204-215. Springer-Verlag, October 2005.
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    BibTex

    @InProceedings{WABI05:EliasHartman_SBT1375,
      author =      {Isaac Elias and Tzvika Hartman},
      title =	{A 1.375-Approximation Algorithm for Sorting by Transpositions},
      booktitle =	{Proc. of the 5th International Workshop on Algorithms in Bioinformatics ({WABI}'05)},
      pages =	{204--214},
      year =	{2005},
      volume =	{3692},
      series =	{Lecture Notes in Computer Science},
      month =	{October},
      publisher =	{Springer-Verlag},
      ISBN =	{3-540-29008-7},
    }