Approximability of packing disjoint cycles

  • Authors:
  • Zachary Friggstad;Mohammad R. Salavatipour

  • Affiliations:
  • Department of Computing Science, University of Alberta, Edmonton, Alberta, Canada;Department of Computing Science, University of Alberta, Edmonton, Alberta, Canada

  • Venue:
  • ISAAC'07 Proceedings of the 18th international conference on Algorithms and computation
  • Year:
  • 2007

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Abstract

Given a graph G, the edge-disjoint cycle packing problem is to find the largest set of cycles of which no two share an edge. For undirected graphs, the best known approximation algorithm has ratio O(√log n) [14,15]. In fact, they proved the same upper bound for the integrality gap of this problem by presenting a simple greedy algorithm. Here we show that this is almost best possible. By modifying integrality gap and hardness results for the edge-disjoint paths problem [1,9], we show that the undirected edge-disjoint cycle packing problem has an integrality gap of Ω(√log n/log log n) and furthermore it is quasi-NP-hard to approximate the edge-disjoint cycle problem within ratio of O(log1/2-Ɛ n) for any constant Ɛ 0. The same results hold for the problem of packing vertex-disjoint cycles.