Martin boundaries and asymptotic behavior of branching random walks

Fuente: arXiv
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Autori principali: Bertacchi, Daniela, Candellero, Elisabetta, Zucca, Fabio
Natura: Preprint
Pubblicazione: 2023
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author Bertacchi, Daniela
Candellero, Elisabetta
Zucca, Fabio
author_facet Bertacchi, Daniela
Candellero, Elisabetta
Zucca, Fabio
contents Let $G$ be an infinite, locally finite graph. We investigate the relation between supercritical, transient branching random walk and the Martin boundary of its underlying random walk. We show results regarding the typical asymptotic directions taken by the particles, and as a consequence we find a new connection between $t$-Martin boundaries and standard Martin boundaries. Moreover, given a subgraph $U$ we study two aspects of branching random walks on $U$: when the trajectories visit $U$ infinitely often (survival) and when they stay inside $U$ forever (persistence). We show that there are cases, when $U$ is not connected, where the branching random walk does not survive in $U$, but the random walk on $G$ converges to the boundary of $U$ with positive probability. In contrast, the branching random walk can survive in $U$ even though the random walk eventually exits $U$ almost surely. We provide several examples and counterexamples.
format Preprint
id arxiv_https___arxiv_org_abs_2308_03711
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Martin boundaries and asymptotic behavior of branching random walks
Bertacchi, Daniela
Candellero, Elisabetta
Zucca, Fabio
Probability
60J80, 60J10, 60J45
Let $G$ be an infinite, locally finite graph. We investigate the relation between supercritical, transient branching random walk and the Martin boundary of its underlying random walk. We show results regarding the typical asymptotic directions taken by the particles, and as a consequence we find a new connection between $t$-Martin boundaries and standard Martin boundaries. Moreover, given a subgraph $U$ we study two aspects of branching random walks on $U$: when the trajectories visit $U$ infinitely often (survival) and when they stay inside $U$ forever (persistence). We show that there are cases, when $U$ is not connected, where the branching random walk does not survive in $U$, but the random walk on $G$ converges to the boundary of $U$ with positive probability. In contrast, the branching random walk can survive in $U$ even though the random walk eventually exits $U$ almost surely. We provide several examples and counterexamples.
title Martin boundaries and asymptotic behavior of branching random walks
topic Probability
60J80, 60J10, 60J45
url https://arxiv.org/abs/2308.03711