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arXiv 0711.2684math.CO
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从Dyck路到321-避免置换的双射

Bijections from Dyck paths to 321-avoiding permutations revisited

David Callan

摘要:

文献中至少有三个从Dyck路径到321-避免置换的双射,分别是Billey-Jockusch-Stanley,Krattenthaler和Mansour-Deng-Du的双射,它们有什么不同?分别记为B,K,M,证明了M = B \circ L = K \circ L',其中L是Dyck路上的经典Kreweras-Lalanne对合,L'也是对合,是L的一种导函数.因此,K^{-1} \circ B,B和K之间的差的度量,是对合L' \circ L的乘积,结果是一个非常奇怪的双射:作为Dyck n-路上的置换,它是“反向路”对合的n次方根。这一事实的证明归结为一个几何参数涉及对不相交的格路径。

英文摘要:

There are (at least) three bijections from Dyck paths to 321-avoiding permutations in the literature, due to Billey-Jockusch-Stanley, Krattenthaler, and Mansour-Deng-Du. How different are they? Denoting them B,K,M respectively, we show that M = B \circ L = K \circ L' where L is the classical Kreweras-Lalanne involution on Dyck paths and L', also an involution, is a sort of derivative of L. Thus K^{-1} \circ B, a measure of the difference between B and K, is the product of involutions L' \circ L and turns out to be a very curious bijection: as a permutation on Dyck n-paths it is an nth root of the "reverse path" involution. The proof of this fact boils down to a geometric argument involving pairs of nonintersecting lattice paths.

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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