Branching random walks with regularly varying perturbations

Fuente: arXiv
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Auteur principal: Kowalski, Krzysztof
Format: Preprint
Publié: 2023
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author Kowalski, Krzysztof
author_facet Kowalski, Krzysztof
contents We consider a modification of classical branching random walk, where we add i.i.d. perturbations to the positions of the particles in each generation. In this model, which was introduced and studied by Bandyopadhyay and Ghosh (2023), perturbations take form $\frac 1 θ\log\frac X E$, where $θ$ is a positive parameter, $X$ has arbitrary distribution $μ$ and $E$ is exponential with parameter 1, independent of $X$. Working under finite mean assumption for $μ$, they proved almost sure convergence of the rightmost position to a constant limit, and identified the weak centered asymptotics when $θ$ does not exceed certain critical parameter $θ_0$. This paper complements their work by providing weak centered asymptotics for the case when $θ> θ_0$ and extending the results to $μ$ with regularly varying tails. We prove almost sure convergence of the rightmost position and identify the appropriate centering for the weak convergence, which is of form $αn + c \log n$, with constants $α$, $c$ depending on the ratio of $θ$ and $θ_0$. We describe the limiting distribution and provide explicitly the constants appearing in the centering.
format Preprint
id arxiv_https___arxiv_org_abs_2308_01571
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Branching random walks with regularly varying perturbations
Kowalski, Krzysztof
Probability
60J80, 60F05, 60F15
We consider a modification of classical branching random walk, where we add i.i.d. perturbations to the positions of the particles in each generation. In this model, which was introduced and studied by Bandyopadhyay and Ghosh (2023), perturbations take form $\frac 1 θ\log\frac X E$, where $θ$ is a positive parameter, $X$ has arbitrary distribution $μ$ and $E$ is exponential with parameter 1, independent of $X$. Working under finite mean assumption for $μ$, they proved almost sure convergence of the rightmost position to a constant limit, and identified the weak centered asymptotics when $θ$ does not exceed certain critical parameter $θ_0$. This paper complements their work by providing weak centered asymptotics for the case when $θ> θ_0$ and extending the results to $μ$ with regularly varying tails. We prove almost sure convergence of the rightmost position and identify the appropriate centering for the weak convergence, which is of form $αn + c \log n$, with constants $α$, $c$ depending on the ratio of $θ$ and $θ_0$. We describe the limiting distribution and provide explicitly the constants appearing in the centering.
title Branching random walks with regularly varying perturbations
topic Probability
60J80, 60F05, 60F15
url https://arxiv.org/abs/2308.01571