Fixed-Parameter tractable algorithms for testing upward planarity

  • Authors:
  • Patrick Healy;Karol Lynch

  • Affiliations:
  • CSIS Department, University of Limerick, Limerick, Ireland;CSIS Department, University of Limerick, Limerick, Ireland

  • Venue:
  • SOFSEM'05 Proceedings of the 31st international conference on Theory and Practice of Computer Science
  • Year:
  • 2005

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Abstract

We consider the problem of testing a digraph G = (V,E) for upward planarity. In particular we present two fixed-parameter tractable algorithms for testing the upward planarity of G. Let n = |V|, let t be the number of triconnected components of G, and let c be the number of cut-vertices of G. The first upward planarity testing algorithm we present runs in O(2t · t! · n2)–time. The previously known best result is an O(t! · 8t · n3 + 23·2c · t3·2c · t! · 8t · n)-time algorithm by Chan. We use the kernelisation technique to develop a second upward planarity testing algorithm which runs in O(n2 + k4(2k + 1)!) time, where k = |E| – |V|. We also define a class of non upward planar digraphs.