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» Improved Steiner tree approximation in graphs
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ESA
2003
Springer
189views Algorithms» more  ESA 2003»
13 years 11 months ago
On the Complexity of Approximating TSP with Neighborhoods and Related Problems
We prove that various geometric covering problems, related to the Travelling Salesman Problem cannot be efficiently approximated to within any constant factor unless P = NP. This ...
Shmuel Safra, Oded Schwartz
SODA
2003
ACM
133views Algorithms» more  SODA 2003»
13 years 7 months ago
Integrality ratio for group Steiner trees and directed steiner trees
The natural relaxation for the Group Steiner Tree problem, as well as for its generalization, the Directed Steiner Tree problem, is a flow-based linear programming relaxation. We...
Eran Halperin, Guy Kortsarz, Robert Krauthgamer, A...
STOC
2010
ACM
295views Algorithms» more  STOC 2010»
13 years 11 months ago
Approximation Schemes for Steiner Forest on Planar Graphs and Graphs of Bounded Treewidth
We give the first polynomial-time approximation scheme (PTAS) for the Steiner forest problem on planar graphs and, more generally, on graphs of bounded genus. As a first step, w...
MohammadHossein Bateni, MohammadTaghi Hajiaghayi a...
ICDE
2009
IEEE
190views Database» more  ICDE 2009»
14 years 8 months ago
Progressive Keyword Search in Relational Databases
A common approach to performing keyword search over relational databases is to find the minimum Steiner trees in database graphs. These methods, however, are rather expensive as th...
Guoliang Li, Xiaofang Zhou, Jianhua Feng, Jianyong...