Approximate k-MSTs and k-Steiner Trees via the Primal-Dual Method and Lagrangean Relaxation

  • Authors:
  • Fabián A. Chudak;Tim Roughgarden;David P. Williamson

  • Affiliations:
  • -;-;-

  • Venue:
  • Proceedings of the 8th International IPCO Conference on Integer Programming and Combinatorial Optimization
  • Year:
  • 2001

Quantified Score

Hi-index 0.00

Visualization

Abstract

We consider the problem of computing the minimum-cost tree spanning at least k vertices in an undirected graph. Garg [10] gave two approximation algorithms for this problem. We show that Garg's algorithms can be explained simply with ideas introduced by Jain and Vazirani for the metric uncapacitated facility location and k-median problems [15], in particular via a Lagrangean relaxation technique together with the primal-dual method for approximation algorithms. We also derive a constant-factor approximation algorithm for the k-Steiner tree problem using these ideas, and point out the common features of these problems that allow them to be solved with similar techniques.