English

An asymptotic result concerning a question of Wilf

Combinatorics 2011-11-14 v1

Abstract

Let Λ\Lambda be a numerical semigroup with embedding dimension e(Λ)e(\Lambda). Define c(Λ)c(\Lambda) to be one plus the largest integer not in Λ\Lambda, and define c(Λ)c'(\Lambda) to be the number of elements in Λ\Lambda less than c(Λ)c(\Lambda). It was asked by Wilf whether c(Λ)c(Λ)1e(Λ)\frac{c'(\Lambda)}{c(\Lambda)} \ge \frac{1}{e(\Lambda)} always holds. We prove an asymptotic version of this conjecture: we show that for a fixed positive integer kk and any ϵ>0\epsilon > 0, the inequality c(Λ)c(Λ)1kϵ\frac{c'(\Lambda)}{c(\Lambda)} \ge \frac{1}{k} - \epsilon holds for all but finitely many numerical semigroups Λ\Lambda satisfying e(Λ)=ke(\Lambda) = k.

Keywords

Cite

@article{arxiv.1111.2779,
  title  = {An asymptotic result concerning a question of Wilf},
  author = {Alex Zhai},
  journal= {arXiv preprint arXiv:1111.2779},
  year   = {2011}
}

Comments

9 pages, submitted to Semigroup Forum