12 citations · 19 across the 6 of their papers we have counts for
6 papers
Involutions on Tip-Augmented Plane Trees for Leaf Interchanging
Laura L. M. Yang, Dax T. X. Zhang
This paper constructs two involutions on tip-augmented plane trees, as defined by Donaghey, that interchange two distinct types of leaves while preserving all other leaves. These t…
Generalizations of Han's Hook Length Identities
Laura L. M. Yang
Han recently discovered new hook length identities for binary trees. In this paper, we extend Han's identities to binomial families of trees. Moreover, we present a bijective proof…
Riordan Paths and Derangements
William Y. C. Chen, Eva Y. P. Deng, Laura L. M. Yang
Riordan paths are Motzkin paths without horizontal steps on the x-axis. We establish a correspondence between Riordan paths and -avoiding derangements. We also pr…
On the Hook Length Formula for Binary Trees
William Y. C. Chen, Laura L. M. Yang
We present a simple combinatorial proof of Postnikov's hook length formula for binary trees.
Parity Reversing Involutions on Plane Trees and 2-Motzkin Paths
William Y. C. Chen, Louis W. Shapiro, Laura L. M. Yang
The problem of counting plane trees with edges and an even or an odd number of leaves was studied by Eu, Liu and Yeh, in connection with an identity on coloring nets due to Sta…
Weighted 2-Motzkin Paths
William Y. C. Chen, Sherry H. F. Yan, Laura L. M. Yang
This paper is motivated by two problems recently proposed by Coker on combinatorial identities related to the Narayana polynomials and the Catalan numbers. We find that a bijection…