Abstract
We study a generalization of the Steiner tree problem, where we are given a weighted network G together with a collection of k subsets of its vertices and a root r. We wish to construct a minimum cost network such that the network supports one unit of flow to the root from every node in a subset simultaneously. The network constructed does not need to support flows from all the subsets simultaneously. We settle an open question regarding the complexity of this problem for k = 2, and give a 3/2 -Approximation algorithm that improves over a (trivial) known 2-Approximation. Furthermore, we prove some structural results that prevent many well-known techniques from doing better than the known O(log n)-Approximation. Despite these obstacles, we conjecture that this problem should have an O(1)-Approximation. We also give an approximation result for a variant of the problem where the solution is required to be a path.
Original language | English |
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Title of host publication | 25th European Symposium on Algorithms, ESA 2017 |
Editors | Christian Sohler, Christian Sohler, Kirk Pruhs |
Publisher | Schloss Dagstuhl - Leibniz-Zentrum für Informatik |
ISBN (Electronic) | 9783959770491 |
DOIs | |
Publication status | Published - 1 Sept 2017 |
Externally published | Yes |
Event | 25th European Symposium on Algorithms, ESA 2017 - Vienna, Austria Duration: 4 Sept 2017 → 6 Sept 2017 |
Publication series
Name | Leibniz International Proceedings in Informatics, LIPIcs |
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Volume | 87 |
ISSN (Print) | 1868-8969 |
Conference
Conference | 25th European Symposium on Algorithms, ESA 2017 |
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Country/Territory | Austria |
City | Vienna |
Period | 4/09/17 → 6/09/17 |
Funding
∗ Full version available at: https://arxiv.org/abs/1707.01487. † This material is based upon work supported in part by National Science Foundation awards CCF-1319811,CCF-1536002, and CCF-1617790. ‡ This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. 2013170941.
Keywords
- Approximation algorithms
- Network design
- Single-commodity flow
- Steiner tree