English

Precise asymptotics of longest cycles in random permutations without macroscopic cycles

Probability 2020-04-22 v1

Abstract

We consider Ewens random permutations of length nn conditioned to have no cycle longer than nβn^\beta with 0<β<10<\beta<1 and to study the asymptotic behaviour as nn\to\infty. We obtain very precise information on the joint distribution of the lengths of the longest cycles; in particular we prove a functional limit theorem where the cumulative number of long cycles converges to a Poisson process in the suitable scaling. Furthermore, we prove convergence of the total variation distance between joint cycle counts and suitable independent Poisson random variables up to a significantly larger maximal cycle length than previously known. Finally, we remove a superfluous assumption from a central limit theorem for the total number of cycles proved in an earlier paper.

Keywords

Cite

@article{arxiv.2004.09904,
  title  = {Precise asymptotics of longest cycles in random permutations without macroscopic cycles},
  author = {Volker Betz and Julian Mühlbauer and Helge Schäfer and Dirk Zeindler},
  journal= {arXiv preprint arXiv:2004.09904},
  year   = {2020}
}
R2 v1 2026-06-23T14:59:35.463Z