Extending Partial Representations of Subclasses of Chordal Graphs

  • Pavel Klavík
  • Jan Kratochvíl
  • Yota Otachi
  • Toshiki Saitoh
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7676)


Chordal graphs are intersection graphs of subtrees in a tree. We investigate complexity of the partial representation extension problem for chordal graphs. A partial representation specifies a tree T′ and some pre-drawn subtrees. It asks whether it is possible to construct a representation inside a modified tree T which extends the partial representation (keeps the pre-drawn subtrees unchanged).

We consider four modifications of T′ and get vastly different problems. In some cases, the problem is interesting even if just T′ is given and no subtree is pre-drawn. Also, we consider three well-known subclasses of chordal graphs: Proper interval graphs, interval graphs and path graphs. We give an almost complete complexity characterization.

In addition, we study parametrized complexity by the number of pre-drawn subtrees, the number of components and the size of the tree T′. We describe an interesting relation with integer partition problems. The problem 3-Partition is used in the NP-completeness reductions. The BinPacking problem is closely related to the extension of interval graphs when space in T′ is limited, and we obtain “equivalency” with BinPacking.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  • Pavel Klavík
    • 1
  • Jan Kratochvíl
    • 1
  • Yota Otachi
    • 2
  • Toshiki Saitoh
    • 3
  1. 1.Department of Applied Mathematics, Faculty of Mathematics and PhysicsCharles UniversityPragueCzech Republic
  2. 2.School of Information ScienceJapan Advanced Institute of Science and TechnologyNomiJapan
  3. 3.Graduate School of EngineeringKobe UniversityNadaJapan

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