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Minimum restricted diameter spanning trees

✍ Scribed by Refael Hassin; Asaf Levin


Publisher
Elsevier Science
Year
2004
Tongue
English
Weight
304 KB
Volume
137
Category
Article
ISSN
0166-218X

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✦ Synopsis


Let G = (V; E) be a requirement graph. Let d = (dij) n i; j=1 be a length metric. For a tree T denote by dT (i; j) the distance between i and j in T (the length according to d of the unique i -j path in T ). The restricted diameter of T , DT , is the maximum distance in T between pair of vertices with requirement between them. The minimum restricted diameter spanning tree problem is to ΓΏnd a spanning tree T such that the restricted diameter is minimized. We prove that the minimum restricted diameter spanning tree problem is NP-hard and that unless P = NP there is no polynomial time algorithm with performance guarantee of less than 2. In the case that G contains isolated vertices and the length matrix is deΓΏned by distances over a tree we prove that there exists a tree over the non-isolated vertices such that its restricted diameter is at most 4 times the minimum restricted diameter and that this constant is at least 3 1 2 . We use this last result to present an O(log(n))-approximation algorithm.


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