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2007

On an Online Spanning Tree Problem in Randomly Weighted Graphs

8 years 12 months ago
On an Online Spanning Tree Problem in Randomly Weighted Graphs
Abstract. This paper is devoted to an online variant of the minimum spanning tree problem in randomly weighted graphs. We assume that the input graph is complete and the edge weights are uniform distributed over [0, 1]. An algorithm receives the edges one by one and has to decide immediately whether to include the current edge into the spanning tree or to reject it. The corresponding edge sequence is determined by some adversary. We propose an algorithm which achieves E [ALG] /E [OPT] = O (1) and E [ALG/OPT] = O (1) against a fair adaptive adversary, i.e., an adversary which determines the edge order online and is fair in a sense that he does not know more about the edge weights than the algorithm. Furthermore, we prove that no online algorithm performs better than E [ALG] /E [OPT] = Ω(log n) if the adversary knows the edge weights in advance. This lower bound is tight, since there is an algorithm which yields E [ALG] /E [OPT] = O (log n) against the strongest imaginable adversary.
Jan Remy, Alexander Souza, Angelika Steger
Added 13 Dec 2010
Updated 13 Dec 2010
Type Journal
Year 2007
Where CPC
Authors Jan Remy, Alexander Souza, Angelika Steger
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