English

Large Deviations for Permutations Avoiding Monotone Patterns

Combinatorics 2016-06-28 v1

Abstract

For a given permutation τ\tau, let PNτP_N^{\tau} be the uniform probability distribution on the set of NN-element permutations σ\sigma that avoid the pattern τ\tau. For τ=μk:=123k\tau=\mu_k:=123\cdots k, we consider PNμk(σI=J)P_N^{\mu_k}(\sigma_I=J) where IγNI\sim \gamma N and JδNJ\sim \delta N for γ,δ(0,1)\gamma,\delta \in (0,1). If γ+δ1\gamma+\delta\neq 1 then we are in the large deviations regime with the probability decaying exponentially, and we calculate the limiting value of PNμk(σI=J)1/NP_N^{\mu_k}(\sigma_I=J)^{1/N}. We also observe that for τ=λk,:=12k(k1)(+1)\tau = \lambda_{k,\ell} := 12\ldots\ell k(k-1)\ldots(\ell+1) and γ+δ<1\gamma+\delta<1, the limit of PNτ(σI=J)1/NP_N^{\tau}(\sigma_I=J)^{1/N} is the same as for τ=μk\tau=\mu_k.

Keywords

Cite

@article{arxiv.1606.07906,
  title  = {Large Deviations for Permutations Avoiding Monotone Patterns},
  author = {Neal Madras and Lerna Pehlivan},
  journal= {arXiv preprint arXiv:1606.07906},
  year   = {2016}
}

Comments

23 pages, 4 figures

R2 v1 2026-06-22T14:34:08.393Z