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

@inproceedings{Chudak2001ApproximateKA,
title={Approximate k-MSTs and k-Steiner Trees via the Primal-Dual Method and Lagrangean Relaxation},
author={Fabi{\'a}n A. Chudak and Tim Roughgarden and David P. Williamson},
booktitle={IPCO},
year={2001}
}

Garg [10] gives two approximation algorithms for the minimum-cost tree spanning k vertices in an undirected graph. Recently Jain and Vazirani [15] discovered primal-dual approximation algorithms for the metric uncapacitated facility location and k-median problems. In this paper we show how Garg’s algorithms can be explained simply with ideas introduced by Jain and Vazirani, in particular via a Lagrangean relaxation technique together with the primal-dual method for approximation algorithms. We… CONTINUE READING