Enumeration of labeled trees and Dyck tilings

Fuente: arXiv
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Autor principal: Shigechi, Keiichi
Formato: Preprint
Publicado: 2024
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author Shigechi, Keiichi
author_facet Shigechi, Keiichi
contents We study a partially ordered set of planar labeled rooted trees by use of combinatorial objects called Dyck tilings. A generating function of the poset is factorized when the minimum element of the poset is $312$-avoiding and satisfies some extra condition. We define a cover relation on rational Dyck tilings by that of labeled trees, and show that increasing and decreasing labelings are dual to each other. We consider two decompositions of a rational $(a,b)$-Dyck tiling: one is into $ab$ Dyck tilings and the other is into $a$ $(1,b)$-Dyck tilings. In the first case, we show that the weight of the $(a,b)$-Dyck tiling is the sum of the weights of $ab$ Dyck tilings. In the second case, we introduce a cover relation on $(1,b)$-Dyck tilings and obtain a poset of $(a,b)$-Dyck tilings by this decomposition.
format Preprint
id arxiv_https___arxiv_org_abs_2408_05483
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Enumeration of labeled trees and Dyck tilings
Shigechi, Keiichi
Combinatorics
We study a partially ordered set of planar labeled rooted trees by use of combinatorial objects called Dyck tilings. A generating function of the poset is factorized when the minimum element of the poset is $312$-avoiding and satisfies some extra condition. We define a cover relation on rational Dyck tilings by that of labeled trees, and show that increasing and decreasing labelings are dual to each other. We consider two decompositions of a rational $(a,b)$-Dyck tiling: one is into $ab$ Dyck tilings and the other is into $a$ $(1,b)$-Dyck tilings. In the first case, we show that the weight of the $(a,b)$-Dyck tiling is the sum of the weights of $ab$ Dyck tilings. In the second case, we introduce a cover relation on $(1,b)$-Dyck tilings and obtain a poset of $(a,b)$-Dyck tilings by this decomposition.
title Enumeration of labeled trees and Dyck tilings
topic Combinatorics
url https://arxiv.org/abs/2408.05483