Moments of density-dependent branching processes and their genealogy

Fuente: arXiv
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Autori principali: André, Mathilde, Foutel-Rodier, Félix, Schertzer, Emmanuel
Natura: Preprint
Pubblicazione: 2025
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author André, Mathilde
Foutel-Rodier, Félix
Schertzer, Emmanuel
author_facet André, Mathilde
Foutel-Rodier, Félix
Schertzer, Emmanuel
contents A density-dependent branching process is a particle system in which individuals reproduce independently, but in a way that depends on the current population size. This feature can model a wide range of ecological interactions at the cost of breaking the branching property. We propose a general approach for studying the genealogy of these models based on moments. Building on a recent work of Bansaye, we show how to compute recursively these moments in a similar spirit to the many-to-few formula in the theory of branching processes. These formulas enable one to deduce the convergence of the genealogy by studying the population density, for which stochastic calculus techniques are available. As a first application of these ideas, we consider a density-dependent branching process started close to a stable equilibrium of the ecological dynamics. We show that, under a finite second moment assumption, its genealogy converges to Kingman's coalescent when the carrying capacity of the population goes to infinity.
format Preprint
id arxiv_https___arxiv_org_abs_2509_05231
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Moments of density-dependent branching processes and their genealogy
André, Mathilde
Foutel-Rodier, Félix
Schertzer, Emmanuel
Probability
60J80
G.3
A density-dependent branching process is a particle system in which individuals reproduce independently, but in a way that depends on the current population size. This feature can model a wide range of ecological interactions at the cost of breaking the branching property. We propose a general approach for studying the genealogy of these models based on moments. Building on a recent work of Bansaye, we show how to compute recursively these moments in a similar spirit to the many-to-few formula in the theory of branching processes. These formulas enable one to deduce the convergence of the genealogy by studying the population density, for which stochastic calculus techniques are available. As a first application of these ideas, we consider a density-dependent branching process started close to a stable equilibrium of the ecological dynamics. We show that, under a finite second moment assumption, its genealogy converges to Kingman's coalescent when the carrying capacity of the population goes to infinity.
title Moments of density-dependent branching processes and their genealogy
topic Probability
60J80
G.3
url https://arxiv.org/abs/2509.05231