English

A bijection between evil-avoiding and rectangular permutations

Combinatorics 2024-10-17 v1

Abstract

Evil-avoiding permutations, introduced by Kim and Williams in 2022, arise in the study of the inhomogeneous totally asymmetric simple exclusion process. Rectangular permutations, introduced by Chiriv\`i, Fang, and Fourier in 2021, arise in the study of Schubert varieties and Demazure modules. Taking a suggestion of Kim and Williams, we supply an explicit bijection between evil-avoiding and rectangular permutations in SnS_n that preserves the number of recoils. We encode these classes of permutations as regular languages and construct a length-preserving bijection between words in these regular languages. We extend the bijection to another Wilf-equivalent class of permutations, namely the 11-almost-increasing permutations, and exhibit a bijection between rectangular permutations and walks of length 2n22n-2 in a path of seven vertices starting and ending at the middle vertex.

Keywords

Cite

@article{arxiv.2301.09530,
  title  = {A bijection between evil-avoiding and rectangular permutations},
  author = {Katherine Tung},
  journal= {arXiv preprint arXiv:2301.09530},
  year   = {2024}
}

Comments

19 pages, 2 figures