Minimum restricted diameter spanning trees
β 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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β¦ 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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