Parking functions, Fubini rankings, and Boolean intervals in the weak order of $\mathfrak{S}_n$

Fuente: arXiv
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Main Authors: Elder, Jennifer, Harris, Pamela E., Kretschmann, Jan, Mori, J. Carlos Martínez
Format: Preprint
Published: 2023
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_version_ 1866916801198161920
author Elder, Jennifer
Harris, Pamela E.
Kretschmann, Jan
Mori, J. Carlos Martínez
author_facet Elder, Jennifer
Harris, Pamela E.
Kretschmann, Jan
Mori, J. Carlos Martínez
contents Let $\mathfrak{S}_n$ denote the symmetric group and let $W(\mathfrak{S}_n)$ denote the weak order of $\mathfrak{S}_n$. Through a surprising connection to a subset of parking functions, which we call unit Fubini rankings, we provide a complete characterization and enumeration for the total number of Boolean intervals in $W(\mathfrak{S}_n)$ and the total number of Boolean intervals of rank $k$ in $W(\mathfrak{S}_n)$. Furthermore, for any $π\in\mathfrak{S}_n$, we establish that the number of Boolean intervals in $W(\mathfrak{S}_n)$ with minimal element $π$ is a product of Fibonacci numbers. We conclude with some directions for further study.
format Preprint
id arxiv_https___arxiv_org_abs_2306_14734
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Parking functions, Fubini rankings, and Boolean intervals in the weak order of $\mathfrak{S}_n$
Elder, Jennifer
Harris, Pamela E.
Kretschmann, Jan
Mori, J. Carlos Martínez
Combinatorics
05A05, 06A07, 05A05, 05A15, 05A19
Let $\mathfrak{S}_n$ denote the symmetric group and let $W(\mathfrak{S}_n)$ denote the weak order of $\mathfrak{S}_n$. Through a surprising connection to a subset of parking functions, which we call unit Fubini rankings, we provide a complete characterization and enumeration for the total number of Boolean intervals in $W(\mathfrak{S}_n)$ and the total number of Boolean intervals of rank $k$ in $W(\mathfrak{S}_n)$. Furthermore, for any $π\in\mathfrak{S}_n$, we establish that the number of Boolean intervals in $W(\mathfrak{S}_n)$ with minimal element $π$ is a product of Fibonacci numbers. We conclude with some directions for further study.
title Parking functions, Fubini rankings, and Boolean intervals in the weak order of $\mathfrak{S}_n$
topic Combinatorics
05A05, 06A07, 05A05, 05A15, 05A19
url https://arxiv.org/abs/2306.14734