Abstract
Let T be a weighted tree with a positive number w(v) associated with each vertex v. A subtree S is a w-central subtree of the weighted tree T if it has the minimum eccentricity \(e_L(S)\) in median graph \(G_{LW}\). A w-central subtree with the minimum vertex weight is called a least w-central subtree of the weighted tree T. In this paper we show that each least w-central subtree of a weighted tree either contains a vertex of the w-centroid or is adjacent to a vertex of the w-centroid. Also, we show that any two least w-central subtrees of a weighted tree either have a nonempty intersection or are adjacent.


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Acknowledgements
This work was partially supported by the National Nature Science Foundation of China (Grant Numbers: 11471210, 11571222). We are very thankful to the referees for their careful reading of this paper and all helpful comments.
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Shan, E., Kang, L. The w-centroids and least w-central subtrees in weighted trees. J Comb Optim 36, 1118–1127 (2018). https://doi.org/10.1007/s10878-017-0174-5
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DOI: https://doi.org/10.1007/s10878-017-0174-5