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Related papers: Results on pattern avoidance in parking functions

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We enumerate interlaced pairs of parking functions whose underlying Dyck path has a bounded height. We obtain an explicit formula for this enumeration in the form of a quotient of analogs of Chebicheff polynomials having coefficients in the…

Combinatorics · Mathematics 2015-04-28 Francois Bergeron

The \emph{Shi arrangement} is the set of all hyperplanes in $\mathbb R^n$ of the form $x_j - x_k = 0$ or $1$ for $1 \le j < k \le n$. Shi observed in 1986 that the number of regions (i.e., connected components of the complement) of this…

Ascent sequences were introduced by Bousquet-Melou et al. in connection with (2+2)-avoiding posets and their pattern avoidance properties were first considered by Duncan and Steingrimsson. In this paper, we consider ascent sequences of…

Combinatorics · Mathematics 2015-02-17 Andrew M. Baxter , Lara K. Pudwell

In 2019, B\'ona and Smith introduced the notion of strong pattern avoidance, saying that a permutation $\pi$ strongly avoids a pattern $\sigma$ if $\pi$ and $\pi^2$ both avoid $\sigma$. Recently, Archer and Geary generalized the idea of…

Combinatorics · Mathematics 2024-05-07 Robin D. P. Zhou , Yongchun Zang

This paper is one of a series whose goal is to enumerate the avoiders, in the sense of classical pattern avoidance, for each triple of 4-letter patterns. There are 317 symmetry classes of triples of 4-letter patterns, avoiders of 267 of…

Combinatorics · Mathematics 2017-08-03 David Callan , Toufik Mansour

We continue the study of parking assortments, a generalization of parking functions introduced by Chen, Harris, Mart\'{i}nez, Pab\'{o}n-Cancel, and Sargent. Given $n$ cars of lengths $\mathbf{y}=(y_1,y_2,\dots,y_n) \in \mathbb{N}^n$, we…

Combinatorics · Mathematics 2023-11-28 Douglas M. Chen

For any irreducible real reflection group $W$ with Coxeter number $h$, Armstrong, Reiner, and the author introduced a pair of $W \times \ZZ_h$-modules which deserve to be called {\sf $W$-parking spaces} which generalize the type A notion of…

Combinatorics · Mathematics 2015-03-20 Brendon Rhoades

We give an improved algorithm for counting the number of $1324$-avoiding permutations, resulting in $14$ further terms of the generating function, which is now known for all patterns of length $\le 50$. We re-analyse the generating function…

Combinatorics · Mathematics 2017-11-21 Andrew R. Conway , Anthony J. Guttmann , Paul Zinn-Justin

Permutations that avoid given patterns have been studied in great depth for their connections to other fields of mathematics, computer science, and biology. From a combinatorial perspective, permutation patterns have served as a unifying…

Combinatorics · Mathematics 2023-06-22 Sylvie Corteel , Megan A. Martinez , Carla D. Savage , Michael Weselcouch

In this paper, we explore parking distributions on caterpillar trees, focusing on two primary statistics: the number of lucky cars and the frequency with which cars prefer specific parking spaces. We use first-return decomposition to reveal…

Combinatorics · Mathematics 2025-09-03 Amanuel T. Getachew

In a scenario of growing usage of park-and-ride facilities, understanding and predicting car park occupancy is becoming increasingly important. This study presents a model that effectively captures the occupancy patterns of park-and-ride…

Applications · Statistics 2025-10-14 Andreas Kaltenbrunner , Josep Ferrer , David Moreno , Vicenç Gómez

We introduce a notion of pattern occurrence that generalizes both classical permutation patterns as well as poset containment. Many questions about pattern statistics and avoidance generalize naturally to this setting, and we focus on…

Combinatorics · Mathematics 2014-09-16 Joshua Cooper , Anna Kirkpatrick

In this paper we consider the enumeration of binary trees avoiding non-contiguous binary tree patterns. We begin by computing closed formulas for the number of trees avoiding a single binary tree pattern with 4 or fewer leaves and compare…

Combinatorics · Mathematics 2012-06-21 Michael Dairyko , Lara Pudwell , Samantha Tyner , Casey Wynn

Motivated by the concept of partial words, we introduce an analogous concept of partial permutations. A partial permutation of length n with k holes is a sequence of symbols $\pi = \pi_1\pi_2 ... \pi_n$ in which each of the symbols from the…

Combinatorics · Mathematics 2015-03-17 Anders Claesson , Vit Jelinek , Eva Jelinkova , Sergey Kitaev

In the set of all patterns in $S_n$, it is clear that each k-pattern occurs equally often. If we instead restrict to the class of permutations avoiding a specific pattern, the situation quickly becomes more interesting. Mikl\'os B\'ona…

Combinatorics · Mathematics 2012-12-03 Cheyne Homberger

Let $\mathcal{C}_n$ denote the set of words $w=w_1\cdots w_n$ on the alphabet of positive integers satisfying $w_{i+1}\leq w_i+1$ for $1 \leq i \leq n-1$ with $w_1=1$. The members of $\mathcal{C}_n$ are known as Catalan words and are…

Combinatorics · Mathematics 2024-05-28 Toufik Mansour , Mark Shattuck

The moduli space $\overline{M}_{0,n}$ may be embedded into the product of projective spaces $\mathbb{P}^1\times \mathbb{P}^2\times \cdots \times \mathbb{P}^{n-3}$, using a combination of the Kapranov map $|\psi_n|:\overline{M}_{0,n}\to…

Algebraic Geometry · Mathematics 2021-10-15 Renzo Cavalieri , Maria Gillespie , Leonid Monin

Partially ordered patterns (POPs) play an important role in the study of permutation patterns, providing a convenient framework for describing large families of classical patterns. The problem of enumerating permutations that avoid POPs has…

Combinatorics · Mathematics 2026-03-05 Shiqi Cao , Huihua Gao , Sergey Kitaev , Yitian Li

A systematic study of avoidance of mesh patterns of length 2 was conducted by Hilmarsson et al., where 25 out of 65 non-equivalent cases were solved. In this paper, we give 27 distribution results for these patterns including 14…

Combinatorics · Mathematics 2019-06-03 Sergey Kitaev , Philip B. Zhang

In 1980, Edelman defined a poset on objects called the noncrossing 2-partitions. They are closely related with noncrossing partitions and parking functions. To some extent, his definition is a precursor of the parking space theory, in the…

Discrete Mathematics · Computer Science 2023-01-06 Bérénice Delcroix-Oger , Matthieu Josuat-Vergès , Lucas Randazzo
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