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arXiv 0906.1844math.CO
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Riordan群与对称格路

The Riordan Group and Symmetric Lattice Paths

Li-Hua Deng, Eva Y. P. Deng, Louis W. Shapiro

摘要:

本文研究了对称格路。令$d_{n}$、$m_{n}$和$s_{n}$分别表示长度为$2n$的对称Dyck路径、对称Motzkin路径和对称Schröder路径的数目。利用Riordan群方法得到了与$d_{n}$,$m_{n}$,$s_{n}$有关的6个恒等式,并给出了其中两个恒等式的组合证明.最后,我们研究了一些特殊Riordan数组的类元所满足的关系,得到了长度为$2n.$的对称Dyck路的平均中高和x轴上的平均点数

英文摘要:

In this paper, we study symmetric lattice paths. Let $d_{n}$, $m_{n}$, and $s_{n}$ denote the number of symmetric Dyck paths, symmetric Motzkin paths, and symmetric Schröder paths of length $2n$, respectively. By using Riordan group methods we obtain six identities relating $d_{n}$, $m_{n}$, and $s_{n}$ and also give two of them combinatorial proofs. Finally, we investigate some relations satisfied by the generic element of some special Riordan arrays and get the average mid-height and the average number of points on the x-axis of symmetric Dyck paths of length $2n.$

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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