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Enumeration of trees by inversions

✍ Scribed by Ira M. Gessel; Bruce E. Sagan; Yeong-Nan Yeh


Publisher
John Wiley and Sons
Year
1995
Tongue
English
Weight
749 KB
Volume
19
Category
Article
ISSN
0364-9024

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✦ Synopsis


Abstract

Mallows and Riordan β€œThe Inversion Enumerator for Labeled Trees,” Bulletin of the American Mathematics Society, vol. 74 [1968] pp. 92‐94) first defined the inversion polynomial, J~n~(q) for trees with n vertices and found its generating function. In the present work, we define inversion polynomials for ordered, plane, and cyclic trees, and find their values at q = 0, Β± 1. Our techniques involve the use of generating functions (including Lagrange inversion), hypergeometric series, and binomial coefficient identities, induction, and bijections. We also derive asymptotic formulae for those results for which we do not have a closed form. Β© 1995 John Wiley & Sons, Inc.


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