Condensation in subcritical Cauchy Bienaymé trees

Fuente: arXiv
Gespeichert in:
Bibliographische Detailangaben
Hauptverfasser: Kortchemski, Igor, Vetter, Leonard
Format: Preprint
Veröffentlicht: 2025
Schlagworte:
Online-Zugang:
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
_version_ 1866908581557698560
author Kortchemski, Igor
Vetter, Leonard
author_facet Kortchemski, Igor
Vetter, Leonard
contents The goal of this note is to study the geometry of large size-conditioned Bienaymé trees whose offspring distribution is subcritical, belongs to the domain of attraction of a stable law of index $α=1$ and satisfies a local regularity assumption. We show that a condensation phenomenon occurs: one unique vertex of macroscopic degree emerges, and its height converges in distribution to a geometric random variable. Furthermore, the height of such trees grows logarithmically in their size. Interestingly, the behavior of subcritical Bienaymée trees with $α=1$ is quite similar to the case $α\in( 1,2]$, in contrast with the critical case. This completes the study of the height of heavy-tailed size-conditioned Bienaymé trees. Our approach is to check that a random-walk one-big-jump principle due to Armendáriz & Loulakis holds, by using local estimates due to Berger, combined with the previous approach to study subcritical Bienaymé trees with $α>1$.
format Preprint
id arxiv_https___arxiv_org_abs_2503_07530
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Condensation in subcritical Cauchy Bienaymé trees
Kortchemski, Igor
Vetter, Leonard
Probability
Primary 60J80, 60G50, 05C05, (Secondary) 05C80
The goal of this note is to study the geometry of large size-conditioned Bienaymé trees whose offspring distribution is subcritical, belongs to the domain of attraction of a stable law of index $α=1$ and satisfies a local regularity assumption. We show that a condensation phenomenon occurs: one unique vertex of macroscopic degree emerges, and its height converges in distribution to a geometric random variable. Furthermore, the height of such trees grows logarithmically in their size. Interestingly, the behavior of subcritical Bienaymée trees with $α=1$ is quite similar to the case $α\in( 1,2]$, in contrast with the critical case. This completes the study of the height of heavy-tailed size-conditioned Bienaymé trees. Our approach is to check that a random-walk one-big-jump principle due to Armendáriz & Loulakis holds, by using local estimates due to Berger, combined with the previous approach to study subcritical Bienaymé trees with $α>1$.
title Condensation in subcritical Cauchy Bienaymé trees
topic Probability
Primary 60J80, 60G50, 05C05, (Secondary) 05C80
url https://arxiv.org/abs/2503.07530