@article{Rothvoß:138778,
title = {On the Complexity of the Asymmetric VPN Problem},
author = {Rothvoß, Thomas and Sanità, Laura},
publisher = {Springer},
journal = {12th Intl. Workshop on Approximation Algorithms for Combinat},
address = {Berlin},
series = {Lecture Notes in Computer Science. 5687},
pages = {326-338},
year = {2009},
abstract = {We give the first constant factor approximation algorithm for the asymmetric Virtual Private Network (VPN) problem with arbitrary concave costs. We even show the stronger result, that there is always a tree solution of cost at most 2 OPT and that a tree solution of (expected) cost at most 49.84 OPT can be determined in polynomial time. Furthermore, we answer an outstanding open question about the complexity status of the so called balanced VPN problem by proving its NP-hardness.},
url = {http://infoscience.epfl.ch/record/138778},
doi = {10.1007/978-3-642-03685-9_25},
}