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The Number of Subtrees of Trees with Given Degree Sequence
Authors:Xiu‐Mei Zhang  Xiao‐Dong Zhang  Daniel Gray  Hua Wang
Institution:1. DEPARTMENT OF MATHEMATICS, SHANGHAI JIAO TONG UNIVERSITY, , SHANGHAI, 200240 P. R. CHINA;2. DEPARTMENT OF MATHEMATICS, SHANGHAI SANDAU UNIVERSITY, , SHANGHAI, 201209 P. R. CHINA;3. DEPARTMENT OF MATHEMATICS, UNIVERSITY OF FLORIDA GAINESVILLE, , FLORIDA, 32611;4. DEPARTMENT OF MATHEMATICAL SCIENCES, GEORGIA SOUTHERN UNIVERSITY STATEBORO, , GEORGIA, 30460
Abstract:This article investigates some properties of the number of subtrees of a tree with given degree sequence. These results are used to characterize trees with the given degree sequence that have the largest number of subtrees, which generalize the recent results of Kirk and Wang (SIAM J Discrete Math 22 (2008), 985–995). These trees coincide with those which were proven by Wang and independently Zhang et al. (2008) to minimize the Wiener index. We also provide a partial ordering of the extremal trees with different degree sequences, some extremal results follow as corollaries.
Keywords:tree  subtree  degree sequence  majorization  05C05  05C30
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