Shape-Wilf-equivalences for vincular patterns
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 and are filling-shape-Wilf-equivalent, we prove that the direct sum is filling-shape-Wilf-equivalent to . We also discover two new pairs of patterns which are filling-shape-Wilf-equivalent: when , , and are nonempty consecutive patterns which are Wilf-equivalent, is filling-shape-Wilf-equivalent to ; and for any consecutive pattern , is filling-shape-Wilf-equivalent to . 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