Descents and des-Wilf Equivalence of Permutations Avoiding Certain Non-Classical Patterns

Abstract

A frequent topic in the study of pattern avoidance is identifying when two sets of patterns $\Pi ,{\Pi }^{\prime }$ are Wilf equivalent, that is, when $|{\text{Av}}_n(\Pi )|=|{\text{Av}}_n({\Pi }^{\prime })|$ for all $n$. In recent work of Dokos et al. the notion of Wilf equivalence was refined to reflect when avoidance of classical patterns preserves certain statistics. In this article, we continue their work by examining $\text{des}$-Wilf equivalence when avoiding certain non-classical patterns.

arXiv comment12 pages