Sciweavers

ENDM
2010
101views more  ENDM 2010»
13 years 4 months ago
Strong Lower Bounds for a Survivable Network Design Problem
We consider a generalization of the Prize Collecting Steiner Tree Problem on a graph with special redundancy requirements on a subset of the customer nodes suitable to model a rea...
Markus Leitner, Günther R. Raidl
SODA
1992
ACM
252views Algorithms» more  SODA 1992»
13 years 5 months ago
A General Approximation Technique for Constrained Forest Problems
We present a general approximation technique for a large class of graph problems. Our technique mostly applies to problems of covering, at minimum cost, the vertices of a graph wit...
Michel X. Goemans, David P. Williamson
SODA
2003
ACM
133views Algorithms» more  SODA 2003»
13 years 5 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...
APPROX
2007
Springer
87views Algorithms» more  APPROX 2007»
13 years 8 months ago
Stochastic Steiner Tree with Non-uniform Inflation
We study the Steiner Tree problem in the model of two-stage stochastic optimization with non-uniform inflation factors, and give a poly-logarithmic approximation factor for this pr...
Anupam Gupta, MohammadTaghi Hajiaghayi, Amit Kumar
MFCS
2001
Springer
13 years 9 months ago
On the Approximability of the Steiner Tree Problem
We show that it is not possible to approximate the minimum Steiner tree problem within 1 + 1 162 unless RP = NP. The currently best known lower bound is 1 + 1 400. The reduction i...
Martin Thimm
STOC
2010
ACM
261views Algorithms» more  STOC 2010»
13 years 9 months ago
An Improved LP-based Approximation for Steiner Tree
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 ...
Jaroslaw Byrka, Fabrizio Grandoni, Thomas Rothvoss...
GECCO
2004
Springer
134views Optimization» more  GECCO 2004»
13 years 10 months ago
Combining a Memetic Algorithm with Integer Programming to Solve the Prize-Collecting Steiner Tree Problem
The prize-collecting Steiner tree problem on a graph with edge costs and vertex profits asks for a subtree minimizing the sum of the total cost of all edges in the subtree plus th...
Gunnar W. Klau, Ivana Ljubic, Andreas Moser, Petra...
GECCO
2004
Springer
123views Optimization» more  GECCO 2004»
13 years 10 months ago
Heuristic Methods for Solving Euclidean Non-uniform Steiner Tree Problems
In this paper, we consider a variation of the Euclidean Steiner Tree Problem in which the space underlying the set of nodes has a specified non-uniform cost structure. This proble...
Ian Frommer, Bruce L. Golden, Guruprasad Pundoor
ICALP
2005
Springer
13 years 10 months ago
Stochastic Steiner Trees Without a Root
Abstract. This paper considers the Steiner tree problem in the model of twostage stochastic optimization with recourse. This model, the focus of much recent research [1–4], tries...
Anupam Gupta, Martin Pál
ICALP
2005
Springer
13 years 10 months ago
Approximation Algorithms for Euclidean Group TSP
In the Euclidean group Traveling Salesman Problem (TSP), we are given a set of points P in the plane and a set of m connected regions, each containing at least one point of P. We w...
Khaled M. Elbassioni, Aleksei V. Fishkin, Nabil H....