On-line Algorithms for Generalized Steiner Tree and Network Connectivity Leasing
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author = {Baruch Awerbuch and Yossi Azar and Yair Bartal},
title = {On-line Algorithms for Generalized Steiner Tree and Network Connectivity Leasing},
year = {}
}
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Abstract:
The Generalized Steiner Tree (GST) problem is defined as follows. We are given a graph with non-negative weights and a set of pairs of vertices. The algorithm has to construct minimum weight subgraph H such that the two nodes of each pair are connected by a path. The off-line problem was studied in [AKR91, GW92], who give good approximation algorithms. We consider the on-line generalized Steiner tree problem, in which pairs of vertices arrive on-line and are needed to be connected immediately. We give a simple O(log 2 n) competitive deterministic on-line algorithm. The previous best algorithm was O( p n log n) competitive [WY93]. We also consider the network connectivity leasing problem which is a generalization of the GST. Here edges of the graph can be either bought or leased for different costs. We provide simple randomized algorithm and more complicated deterministic one which achieve poly-logarithmic competitive ratios. Johns Hopkins University and Lab. for Computer Science,...
