Approximating Steiner Networks with Node-Weights

The (undirected) Steiner Network problem is: given a graph = ( , ) with edge/node-weights and edge-connectivity requirements { ( , ) : , }, find a minimumweight subgraph of containing so that the -edge-connectivity in is at least ( , ) for all , . The seminal paper of Jain [16], and numerous papers preceding it, considered the EdgeWeighted Steiner Network problem, with weights on the edges only, and developed novel tools for approximating minimum-weight edge-covers of several types of set functions and families. However, for the Node-Weighted Steiner Network (NWSN) problem, nontrivial approximation algorithms were known only for 0, 1 requirements. We make an attempt to change this situation, by giving the first non-trivial approximation algorithm for NWSN with arbitrary requirements. Our approximation ratio for NWSN is max (ln ), where max = max , ( , ). This generalizes the result of Klein and Ravi [18] for

• Type: Journal
• Year: 2010
• Where: SIAMCOMP
• Authors: Zeev Nutov
• Keywords: Approximation Algorithm, SIAMCOMP 2010, Steiner Network, Steiner Network Problem