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Bibliographic Details
Main Authors: Addario-Berry, Louigi, Arias, Arturo Arellano, Lin, Jessica
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.10515
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author Addario-Berry, Louigi
Arias, Arturo Arellano
Lin, Jessica
author_facet Addario-Berry, Louigi
Arias, Arturo Arellano
Lin, Jessica
contents We consider the long-time behaviour of binary branching Brownian motion (BBM) where the branching rate depends on a periodic spatial heterogeneity. We prove that almost surely as $t\to\infty$, the heterogeneous BBM at time $t$, normalized by $t$, approaches a deterministic convex shape with respect to Hausdorff distance. Our approach relies on establishing tail bounds on the probability of existence of BBM particles lying in half-spaces, which in particular yields the asymptotic speed of propagation of projections of the BBM in every direction. Our arguments are primarily probabilistic in nature, but additionally exploit the existence of a "front speed" (or minimal speed of a pulsating traveling front solution) for the Fisher-KPP reaction-diffusion equation naturally associated to the BBM.
format Preprint
id arxiv_https___arxiv_org_abs_2507_10515
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A shape theorem for BBM in a periodic environment
Addario-Berry, Louigi
Arias, Arturo Arellano
Lin, Jessica
Probability
60J80, 60F15, 35K57, 35B40
We consider the long-time behaviour of binary branching Brownian motion (BBM) where the branching rate depends on a periodic spatial heterogeneity. We prove that almost surely as $t\to\infty$, the heterogeneous BBM at time $t$, normalized by $t$, approaches a deterministic convex shape with respect to Hausdorff distance. Our approach relies on establishing tail bounds on the probability of existence of BBM particles lying in half-spaces, which in particular yields the asymptotic speed of propagation of projections of the BBM in every direction. Our arguments are primarily probabilistic in nature, but additionally exploit the existence of a "front speed" (or minimal speed of a pulsating traveling front solution) for the Fisher-KPP reaction-diffusion equation naturally associated to the BBM.
title A shape theorem for BBM in a periodic environment
topic Probability
60J80, 60F15, 35K57, 35B40
url https://arxiv.org/abs/2507.10515