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arXiv 1010.5673math.CO
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Dyck路上的外对和上阶统计量

Exterior Pairs and Up Step Statistics on Dyck Paths

Sen-Peng Eu, Tung-Shan Fu

摘要:

令$\C_n$为长度为$n$的Dyck路径的集合。本文利用有序树的一个新的自同构,证明了A.丹尼斯和R. Simion,在集合$\C_n$上是等分布的,具有统计量“在高度$h$处的上升台阶数,具有$h\equiv 0$(mod 3”)“。此外,对于$m\ge 3$,我们证明了集合$\C_n$上的两个统计量“在高度$h$上的向上台阶数与$h\equiv 0$(mod $m$)”和“在高度$h$上的向上台阶数与$h\equiv m-1$(mod $m$)”是“几乎等分布的”。这两个结果都得到了组合证明。

英文摘要:

Let $\C_n$ be the set of Dyck paths of length $n$. In this paper, by a new automorphism of ordered trees, we prove that the statistic `number of exterior pairs', introduced by A. Denise and R. Simion, on the set $\C_n$ is equidistributed with the statistic `number of up steps at height $h$ with $h\equiv 0$ (mod 3)'. Moreover, for $m\ge 3$, we prove that the two statistics `number of up steps at height $h$ with $h\equiv 0$ (mod $m$)' and `number of up steps at height $h$ with $h\equiv m-1$ (mod $m$)' on the set $\C_n$ are `almost equidistributed'. Both results are proved combinatorially.

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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