Approximating the Generalized Terminal Backup Problem via Half-integral Multiflow Relaxation

Author Takuro Fukunaga

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Takuro Fukunaga

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Takuro Fukunaga. Approximating the Generalized Terminal Backup Problem via Half-integral Multiflow Relaxation. In 32nd International Symposium on Theoretical Aspects of Computer Science (STACS 2015). Leibniz International Proceedings in Informatics (LIPIcs), Volume 30, pp. 316-328, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2015)


We consider a network design problem called the generalized terminal backup problem. Whereas earlier work investigated the edge-connectivity constraints only, we consider both edge- and node-connectivity constraints for this problem. A major contribution of this paper is the development of a strongly polynomial-time 4/3-approximation algorithm for the problem. Specifically, we show that a linear programming relaxation of the problem is half-integral, and that the half-integral optimal solution can be rounded to a 4/3-approximate solution. We also prove that the linear programming relaxation of the problem with the edge-connectivity constraints is equivalent to minimizing the cost of half-integral multiflows that satisfy flow demands given from terminals. This observation implies a strongly polynomial-time algorithm for computing a minimum cost half-integral multiflow under flow demand constraints.
  • survivable network design
  • multiflow
  • LP rounding


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