28 search results - page 2 / 6 » Lower bounds for the relative greedy algorithm for approxima... |
SODA
2003
ACM
13 years 7 months ago
2003
ACM
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...
ESA
2008
Springer
13 years 7 months ago
2008
Springer
The edge asymmetry of a directed, edge-weighted graph is defined as the maximum ratio of the weight of antiparallel edges in the graph, and can be used as a measure of the heterog...
STOC
2010
ACM
13 years 10 months ago
2010
ACM
The Steiner tree problem is one of the most fundamental ÆÈ-hard problems: given a weighted undirected graph and a subset of terminal nodes, find a minimum weight tree spanning ...
STOC
2010
ACM
13 years 10 months ago
2010
ACM
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...
ESA
2003
Springer
13 years 11 months ago
2003
Springer
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 ...