English

Rooted forests that avoid sets of permutations

Combinatorics 2017-10-02 v3

Abstract

We say that an unordered rooted labeled forest avoids the pattern πSn\pi\in\mathcal{S}_n if the sequence obtained from the labels along the path from the root to any vertex does not contain a subsequence that is in the same relative order as π\pi. We enumerate several classes of forests that avoid certain sets of permutations, including the set of unimodal forests, via bijections with set partitions with certain properties. We also define and investigate an analog of Wilf-equivalence for forests.

Keywords

Cite

@article{arxiv.1607.03046,
  title  = {Rooted forests that avoid sets of permutations},
  author = {Katie Anders and Kassie Archer},
  journal= {arXiv preprint arXiv:1607.03046},
  year   = {2017}
}

Comments

13 pages, 7 figures

R2 v1 2026-06-22T14:51:26.555Z