English

On 102-avoiding inversion sequences

Combinatorics 2025-06-04 v1

Abstract

In this article, we provide a bijection between the set of inversion sequences avoiding the pattern 102 and the set of 2-Schr\"{o}der paths having neither peaks nor valleys and ending with a diagonal step. To achieve this, we introduce two intermediate objects, called UVD paths and labeled FF-paths, and establish bijections among all four families. For each of these combinatorial objects, we define a natural statistic and enumerate the corresponding structures with respect to this statistic. In addition, we study inversion sequences avoiding 102 and another pattern of length 3, providing refined enumerations according to the same statistic.

Keywords

Cite

@article{arxiv.2506.02985,
  title  = {On 102-avoiding inversion sequences},
  author = {JiSun Huh and Sangwook Kim and Seunghyun Seo and Heesung Shin},
  journal= {arXiv preprint arXiv:2506.02985},
  year   = {2025}
}

Comments

23 pages, 4 figures