English

Counterbalancing steps at random in a random walk

Probability 2022-07-05 v2 Combinatorics

Abstract

A random walk with counterbalanced steps is a process of partial sums Sˇ(n)=Xˇ1++Xˇn\check S(n)=\check X_1+ \cdots + \check X_n whose steps Xˇn\check X_n are given recursively as follows. For each n2n\geq 2, with a fixed probability pp, Xˇn\check X_n is a new independent sample from some fixed law μ\mu, and with complementary probability 1p1-p, Xˇn=Xˇv(n)\check X_n= -\check X_{v(n)} counterbalances a previous step, with v(n)v(n) a uniform random pick from {1,,n1}\{1, \ldots, n-1\}. We determine the asymptotic behavior of Sˇ(n)\check S(n) in terms of pp and the first two moments of μ\mu. Our approach relies on a coupling with a reinforcement algorithm due to H.A. Simon, and on properties of random recursive trees and Eulerian numbers, which may be of independent interest. The method can be adapted to the situation where the step distribution μ\mu belongs to the domain of attraction of a stable law.

Keywords

Cite

@article{arxiv.2011.14069,
  title  = {Counterbalancing steps at random in a random walk},
  author = {Jean Bertoin},
  journal= {arXiv preprint arXiv:2011.14069},
  year   = {2022}
}

Comments

To appear in J.Eur.Math.Soc

R2 v1 2026-06-23T20:34:01.125Z