The optimal base of a matroid/with tree-type constraints |
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Authors: | Jue Xue |
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Institution: | 1. Institute of Systems Science, Academia Sinica, China
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Abstract: | LetM be a matroid defined on a weighted finite setE=(e 1, ...,e n ).l(e) is the weight ofe∈E. P=(X 1, ...,X m ) is a set of subsets ofE. ?X i ,X j ∈P, ifX i ∩X j ≠ø (the empty set), then eitherX i ?X j orX j ?X i . For eachX i ∈P, there are two associate nonnegative integersa i andb i witha i ≤b i ≤|X i |. We call a baseT ofM a feasible base with respect toP (or simply call it a feasible base ofM), if ?X i ∈P,a i ≤|X i ∩T|≤b i . A baseT′ is called optimal if: - T′ is feasible,
- \(l(T') = \sum\limits_{e \in T'} {l(e) = \min (\sum\limits_{e \in T} {l(e)|T} }\) is a feasible base ofM).
In this paper we present a polynomial algorithm to solve the optimal base problem. |
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