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On the Hardness of Recognizing Bundles in Time Table Graphs

  • Annegret Liebers
  • Dorothea Wagner
  • Karsten Weihe
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1665)

Abstract

In a cooperation with the national German railway company, we construct a directed graph from a set of train time tables where train stations correspond to vertices, and where pairs of consecutive stops of trains correspond to edges. We consider the problem of locating vertices of this time table graph that intuitively correspond to train stations where the underlying railroad network branches into several directions, and that induce a partition of the edge set into bundles.

We formulate this problem as a graph theoretic optimization problem, and show for two versions of the problem that they are NP-hard. For the first version we show that it is even NP-complete to decide whether any other solution besides the trivial one exists.

Keywords

Variable Component Directed Graph Force Component Hamilton Path Truth Assignment 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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    Thomas J. Schaefer. The complexity of satisfiability problems. In Proceedings of the 10th Annual ACM Symposium on Theory of Computing, STOC’78, pages 216–226, 1978. 333Google Scholar
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    Karsten Weihe, Ulrik Brandes, Annegret Liebers, Matthias Müller-Hannemann, Dorothea Wagner, and Thomas Willhalm. Empirical Design of Geometric Algorithms. In Proceedings of the 15th ACM Symposium on Computational Geometry, SCG’99, pages 86–94, 1999. 326Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Annegret Liebers
    • 1
  • Dorothea Wagner
    • 1
  • Karsten Weihe
    • 1
  1. 1.University of Konstanz Faculty of Mathematics and Computer ScienceKonstanzGermany

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