English

Shape-Wilf-equivalences for vincular patterns

Combinatorics 2013-02-05 v3

Abstract

We extend the notion of shape-Wilf-equivalence to vincular patterns (also known as "generalized patterns" or "dashed patterns"). First we introduce a stronger equivalence on patterns which we call filling-shape-Wilf-equivalence. When vincular patterns α\alpha and β\beta are filling-shape-Wilf-equivalent, we prove that the direct sum ασ\alpha\oplus\sigma is filling-shape-Wilf-equivalent to βσ\beta\oplus\sigma. We also discover two new pairs of patterns which are filling-shape-Wilf-equivalent: when α\alpha, β\beta, and σ\sigma are nonempty consecutive patterns which are Wilf-equivalent, ασ\alpha\oplus\sigma is filling-shape-Wilf-equivalent to βσ\beta\oplus\sigma; and for any consecutive pattern α\alpha, 1α1\oplus\alpha is filling-shape-Wilf-equivalent to 1α1\ominus\alpha. These equivalences generalize Wilf-equivalences found by Elizalde and Kitaev. These new equivalences imply many new Wilf-equivalences for vincular patterns

Cite

@article{arxiv.1201.4767,
  title  = {Shape-Wilf-equivalences for vincular patterns},
  author = {Andrew M. Baxter},
  journal= {arXiv preprint arXiv:1201.4767},
  year   = {2013}
}

Comments

15 pages, 7 figures, 1 table. Presented at Permutation Patterns 2012; Accepted to Advanced in Applied Mathematics

R2 v1 2026-06-21T20:08:31.116Z