Rowmotion on hook and two-row alt $ν$-Tamari lattices

Fuente: arXiv
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Main Authors: Eu, Sen-Peng, Hioe, Vei-Cheng, Lee, Yi-Lin
Format: Preprint
Published: 2026
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author Eu, Sen-Peng
Hioe, Vei-Cheng
Lee, Yi-Lin
author_facet Eu, Sen-Peng
Hioe, Vei-Cheng
Lee, Yi-Lin
contents In 2024, Ceballos and Chenevi{è}re introduced alt $ν$-Tamari lattices, parameterized by a lattice path $ν$ and an increment vector $δ$, as a common generalization of $ν$-Tamari and $ν$-Dyck lattices. We study rowmotion on two families: the alt hook-Tamari lattice $\mathsf{H}_δ(a,b)$ (where $ν=EN^{a-1}E^{b-1}N$) and the alt $2$-row-Tamari lattice $\mathsf{T}_δ(a,b)$ (where $ν=E^aNE^bN$). We explicitly determine the orbit structures of $\mathsf{H}_δ(a,b)$ and $\mathsf{T}_δ(a,b)$ under rowmotion, and prove that their orbit structures are independent of the increment vector $δ$. As a consequence, we show that rowmotion on $\mathsf{H}_δ(a,b)$ exhibits the cyclic sieving phenomenon. We also compute orbit sums for several natural statistics. In the hook case, we evaluate the down-degree, peak, valley, and area statistics; in the $2$-row case, we focus on the down-degree statistic. All of these -- except for the area statistic -- are homometric under rowmotion. Regarding the methodology of this paper, our results in the hook case are obtained by applying a simple local modification to their Hasse diagrams. In the $2$-row case, we introduce a switching property for semidistributive lattices, which allows us to compare the orbit structures arising from different increment vectors.
format Preprint
id arxiv_https___arxiv_org_abs_2605_29431
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rowmotion on hook and two-row alt $ν$-Tamari lattices
Eu, Sen-Peng
Hioe, Vei-Cheng
Lee, Yi-Lin
Combinatorics
05A15, 05E18, 06D10, 06D75
In 2024, Ceballos and Chenevi{è}re introduced alt $ν$-Tamari lattices, parameterized by a lattice path $ν$ and an increment vector $δ$, as a common generalization of $ν$-Tamari and $ν$-Dyck lattices. We study rowmotion on two families: the alt hook-Tamari lattice $\mathsf{H}_δ(a,b)$ (where $ν=EN^{a-1}E^{b-1}N$) and the alt $2$-row-Tamari lattice $\mathsf{T}_δ(a,b)$ (where $ν=E^aNE^bN$). We explicitly determine the orbit structures of $\mathsf{H}_δ(a,b)$ and $\mathsf{T}_δ(a,b)$ under rowmotion, and prove that their orbit structures are independent of the increment vector $δ$. As a consequence, we show that rowmotion on $\mathsf{H}_δ(a,b)$ exhibits the cyclic sieving phenomenon. We also compute orbit sums for several natural statistics. In the hook case, we evaluate the down-degree, peak, valley, and area statistics; in the $2$-row case, we focus on the down-degree statistic. All of these -- except for the area statistic -- are homometric under rowmotion. Regarding the methodology of this paper, our results in the hook case are obtained by applying a simple local modification to their Hasse diagrams. In the $2$-row case, we introduce a switching property for semidistributive lattices, which allows us to compare the orbit structures arising from different increment vectors.
title Rowmotion on hook and two-row alt $ν$-Tamari lattices
topic Combinatorics
05A15, 05E18, 06D10, 06D75
url https://arxiv.org/abs/2605.29431