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EJC
2008

On Postnikov's hook length formula for binary trees

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On Postnikov's hook length formula for binary trees
We present a combinatorial proof of Postnikov's hook length formula for binary trees. c 2007 Elsevier Ltd. All rights reserved. Let [n] = {1, 2, . . . , n}. It is well known that the number of labeled trees on [n] equals nn-2, and the number of rooted trees on [n] equals nn-1 [5,8]. Recently, Postnikov derived an identity on binary trees and asked for a combinatorial proof [6]. We adopt the terminology of Postnikov [6]. Given a binary tree T and a vertex v of T , we use h(v) to denote the hook length of v, namely, the number of descendants of v (including v itself). Postnikov's hook length formula for binary trees reads as follows.
William Y. C. Chen, Laura L. M. Yang
Added 10 Dec 2010
Updated 10 Dec 2010
Type Journal
Year 2008
Where EJC
Authors William Y. C. Chen, Laura L. M. Yang
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