 
Summary: Chapter 9
Online Generalized Steiner Problem
Baruch Awerbuch \Lambda Yossi Azar y Yair Bartal z
Abstract
The Generalized Steiner Problem (GSP) is defined
as follows. We are given a graph with nonnegative
weights and a set of pairs of vertices. The algorithm
has to construct minimum weight subgraph such that
the two nodes of each pair are connected by a path.
Offline generalized Steiner problem approxima
tion algorithms were given in [AKR91, GW92].
We consider the online generalized Steiner prob
lem, in which pairs of vertices arrive online and are
needed to be connected immediately.
We give a simple O(log 2 n) competitive determin
istic online algorithm. The previous best algorithm
was O(
p
n log n) competitive [WY93].
We also consider the network connectivity leasing
