Extremal process of the local time of simple random walk on a regular tree

Fuente: arXiv
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Hauptverfasser: Abe, Yoshihiro, Biskup, Marek
Format: Preprint
Veröffentlicht: 2025
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author Abe, Yoshihiro
Biskup, Marek
author_facet Abe, Yoshihiro
Biskup, Marek
contents We study a continuous-time simple random walk on a regular rooted tree of depth $n$ in two settings: either the walk is started from a leaf vertex and run until the tree root is first hit or it is started from the root and run until it has spent a prescribed amount of time there. In both cases we show that the extremal process associated with centered square-root local time on the leaves tends, as $n\to\infty$, to a decorated Poisson point process with a random intensity measure. While the intensity measure is specific to the local-time problem at hand, the decorations are exactly those for the tree-indexed Markov chain (a.k.a. Branching Random Walk or Gaussian Free Field) with normal step distribution. The proof demonstrates the latter by way of a Lindeberg-type swap of the decorations of the two processes which itself relies on a well-known isomorphism theorem.
format Preprint
id arxiv_https___arxiv_org_abs_2506_09592
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extremal process of the local time of simple random walk on a regular tree
Abe, Yoshihiro
Biskup, Marek
Probability
60G50, 60G70, 05C81
We study a continuous-time simple random walk on a regular rooted tree of depth $n$ in two settings: either the walk is started from a leaf vertex and run until the tree root is first hit or it is started from the root and run until it has spent a prescribed amount of time there. In both cases we show that the extremal process associated with centered square-root local time on the leaves tends, as $n\to\infty$, to a decorated Poisson point process with a random intensity measure. While the intensity measure is specific to the local-time problem at hand, the decorations are exactly those for the tree-indexed Markov chain (a.k.a. Branching Random Walk or Gaussian Free Field) with normal step distribution. The proof demonstrates the latter by way of a Lindeberg-type swap of the decorations of the two processes which itself relies on a well-known isomorphism theorem.
title Extremal process of the local time of simple random walk on a regular tree
topic Probability
60G50, 60G70, 05C81
url https://arxiv.org/abs/2506.09592