Poissonization-based collision threshold derivation for random walks on lattices

Fuente: arXiv
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Main Author: Burton, Zachary
Format: Preprint
Published: 2025
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_version_ 1866915274106601472
author Burton, Zachary
author_facet Burton, Zachary
contents In this expository note, we give a short derivation of the expected number of collisions between two independent simple random walkers on integer lattices. Adapting a Poissonization technique introduced by Lange, we express the collision probability as the return probability of the continuous-time difference walk, given by a modified Bessel function. Analyzing its asymptotic decay yields a clean, self-contained proof that the expected number of collisions in $\mathbb{Z}^d$ is finite if and only if $d\geq3$. We also provide a general formula for the asymptotic number of collisions.
format Preprint
id arxiv_https___arxiv_org_abs_2505_02973
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Poissonization-based collision threshold derivation for random walks on lattices
Burton, Zachary
Probability
60J27 (primary) 60G50, 33C10 (secondary)
In this expository note, we give a short derivation of the expected number of collisions between two independent simple random walkers on integer lattices. Adapting a Poissonization technique introduced by Lange, we express the collision probability as the return probability of the continuous-time difference walk, given by a modified Bessel function. Analyzing its asymptotic decay yields a clean, self-contained proof that the expected number of collisions in $\mathbb{Z}^d$ is finite if and only if $d\geq3$. We also provide a general formula for the asymptotic number of collisions.
title Poissonization-based collision threshold derivation for random walks on lattices
topic Probability
60J27 (primary) 60G50, 33C10 (secondary)
url https://arxiv.org/abs/2505.02973