Coexistence for Competing Branching Random Walks with Identical Asymptotic Shape on $\mathbb{Z}^d$

Fuente: arXiv
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Auteurs principaux: Ghosh, Partha Pratim, Jahnel, Benedikt
Format: Preprint
Publié: 2025
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author Ghosh, Partha Pratim
Jahnel, Benedikt
author_facet Ghosh, Partha Pratim
Jahnel, Benedikt
contents We consider two independent branching random walks that start next to each other on the $d$-dimensional hypercubic lattice and that carry two different colors. Vertices of the lattice are colored according to the color of the walker cloud that first visits the vertex, leading to the question of possible coexistence in the sense that both colors appear on infinitely many vertices. Under mild conditions, we prove the coexistence for two independently distributed branching random walks obeying the same first- and second-order behavior for their extremal particles. To complement this result, we also exhibit examples for the almost-sure absence of coexistence, for $d=1$, in cases where the asymptotic shapes of the walker clouds are calibrated to coincide, thereby answering a question by Deijfen and Vilkas (ECP 28(15):1-11, 2023). As a main tool we employ second-order and large-deviation approximations for the position of the extremal particles in one-dimensional branching random walks.
format Preprint
id arxiv_https___arxiv_org_abs_2512_09153
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Coexistence for Competing Branching Random Walks with Identical Asymptotic Shape on $\mathbb{Z}^d$
Ghosh, Partha Pratim
Jahnel, Benedikt
Probability
Primary: 60D05, Secondary: 60K35
We consider two independent branching random walks that start next to each other on the $d$-dimensional hypercubic lattice and that carry two different colors. Vertices of the lattice are colored according to the color of the walker cloud that first visits the vertex, leading to the question of possible coexistence in the sense that both colors appear on infinitely many vertices. Under mild conditions, we prove the coexistence for two independently distributed branching random walks obeying the same first- and second-order behavior for their extremal particles. To complement this result, we also exhibit examples for the almost-sure absence of coexistence, for $d=1$, in cases where the asymptotic shapes of the walker clouds are calibrated to coincide, thereby answering a question by Deijfen and Vilkas (ECP 28(15):1-11, 2023). As a main tool we employ second-order and large-deviation approximations for the position of the extremal particles in one-dimensional branching random walks.
title Coexistence for Competing Branching Random Walks with Identical Asymptotic Shape on $\mathbb{Z}^d$
topic Probability
Primary: 60D05, Secondary: 60K35
url https://arxiv.org/abs/2512.09153