On the cover time of Brownian motion on the Brownian continuum random tree

Fuente: arXiv
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Main Authors: Andriopoulos, George, Croydon, David A., Margarint, Vlad, Menard, Laurent
Format: Preprint
Published: 2024
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author Andriopoulos, George
Croydon, David A.
Margarint, Vlad
Menard, Laurent
author_facet Andriopoulos, George
Croydon, David A.
Margarint, Vlad
Menard, Laurent
contents Upon almost-every realisation of the Brownian continuum random tree (CRT), it is possible to define a canonical diffusion process or `Brownian motion'. The main result of this article establishes that the cover time of the Brownian motion on the Brownian CRT (i.e.\ the time taken by the process in question to visit the entire state space) is equal to the infimum over the times at which the associated local times are strictly positive everywhere. The proof of this result depends on the recursive self-similarity of the Brownian CRT and a novel version of the first Ray-Knight theorem for trees, which is of independent interest. As a consequence, we obtain that the suitably-rescaled cover times of simple random walks on critical, finite variance Galton-Watson trees converge in distribution with respect to their annealed laws to the cover time of Brownian motion on the Brownian CRT. Other families of graphs that have the Brownian CRT as a scaling limit are also covered. Additionally, we partially confirm a 1991 conjecture of David Aldous regarding related cover-and-return times.
format Preprint
id arxiv_https___arxiv_org_abs_2410_03922
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the cover time of Brownian motion on the Brownian continuum random tree
Andriopoulos, George
Croydon, David A.
Margarint, Vlad
Menard, Laurent
Probability
60K37 (primary), 05C81, 60G17, 60J55, 60J68
Upon almost-every realisation of the Brownian continuum random tree (CRT), it is possible to define a canonical diffusion process or `Brownian motion'. The main result of this article establishes that the cover time of the Brownian motion on the Brownian CRT (i.e.\ the time taken by the process in question to visit the entire state space) is equal to the infimum over the times at which the associated local times are strictly positive everywhere. The proof of this result depends on the recursive self-similarity of the Brownian CRT and a novel version of the first Ray-Knight theorem for trees, which is of independent interest. As a consequence, we obtain that the suitably-rescaled cover times of simple random walks on critical, finite variance Galton-Watson trees converge in distribution with respect to their annealed laws to the cover time of Brownian motion on the Brownian CRT. Other families of graphs that have the Brownian CRT as a scaling limit are also covered. Additionally, we partially confirm a 1991 conjecture of David Aldous regarding related cover-and-return times.
title On the cover time of Brownian motion on the Brownian continuum random tree
topic Probability
60K37 (primary), 05C81, 60G17, 60J55, 60J68
url https://arxiv.org/abs/2410.03922