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Main Author: Ligonnière, Maxime
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2312.12088
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author Ligonnière, Maxime
author_facet Ligonnière, Maxime
contents This article is devoted to the study of products of random operators of the form $M_{0,n}=M_0\cdots M_{n-1}$, where $(M_{n})_{n\in\mathbb{N}}$ is an ergodic sequence of positive operators on the space of signed measures on a space $\mathbb{X}$. Under suitable conditions, in particular, a Doeblin-type minoration suited for non conservative operators, we obtain asymptotic results of the form \[ μM_{0,n} \simeq μ(\tilde{h}) r_n π_n,\] where $\tilde{h}$ is a random bounded function, $(r_n)_{n\geq 0}$ is a random non negative sequence and $π_n$ is a random probability measure on $\mathbb{X}$. Moreover, $\tilde{h}$, $(r_n)$ and $π_n$ do not depend on the choice of the measure $μ$. We prove additionally that $n^{-1} \log (r_n)$ converges almost surely to the Lyapunov exponent $λ$ of the process $(M_{0,n})_{n\geq 0}$ and that the sequence of random probability measures $(π_n)$ converges weakly towards a random probability measure. These results are analogous to previous estimates from Hennion in the case of $d\times d$ matrices, that were obtained with different techniques, based on a projective contraction in Hilbert distance. In the case where the sequence $(M_n)$ is i.i.d, we additionally exhibit an expression of the Lyapunov exponent $λ$ as an integral with respect to the weak limit of the sequence of random probability measures $(π_n)$ and exhibit an oscillation behavior of $r_n$ when $λ=0$. We provide a detailed comparison of our assumptions with the ones of Hennion and present some example of applications of our results, in particular in the field of population dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2312_12088
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Ergodic behavior of products of random positive operators
Ligonnière, Maxime
Probability
This article is devoted to the study of products of random operators of the form $M_{0,n}=M_0\cdots M_{n-1}$, where $(M_{n})_{n\in\mathbb{N}}$ is an ergodic sequence of positive operators on the space of signed measures on a space $\mathbb{X}$. Under suitable conditions, in particular, a Doeblin-type minoration suited for non conservative operators, we obtain asymptotic results of the form \[ μM_{0,n} \simeq μ(\tilde{h}) r_n π_n,\] where $\tilde{h}$ is a random bounded function, $(r_n)_{n\geq 0}$ is a random non negative sequence and $π_n$ is a random probability measure on $\mathbb{X}$. Moreover, $\tilde{h}$, $(r_n)$ and $π_n$ do not depend on the choice of the measure $μ$. We prove additionally that $n^{-1} \log (r_n)$ converges almost surely to the Lyapunov exponent $λ$ of the process $(M_{0,n})_{n\geq 0}$ and that the sequence of random probability measures $(π_n)$ converges weakly towards a random probability measure. These results are analogous to previous estimates from Hennion in the case of $d\times d$ matrices, that were obtained with different techniques, based on a projective contraction in Hilbert distance. In the case where the sequence $(M_n)$ is i.i.d, we additionally exhibit an expression of the Lyapunov exponent $λ$ as an integral with respect to the weak limit of the sequence of random probability measures $(π_n)$ and exhibit an oscillation behavior of $r_n$ when $λ=0$. We provide a detailed comparison of our assumptions with the ones of Hennion and present some example of applications of our results, in particular in the field of population dynamics.
title Ergodic behavior of products of random positive operators
topic Probability
url https://arxiv.org/abs/2312.12088