Atypical stars on a directed landscape geodesic

Fuente: arXiv
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Main Author: Bhatia, Manan
Format: Preprint
Published: 2022
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author Bhatia, Manan
author_facet Bhatia, Manan
contents In random geometry, a recurring theme is that any two geodesics emanating from a typical point part ways at a strictly positive distance from the above point, and we call such points as $1$-stars. However, the measure zero set of atypical stars, the points where such coalescence fails, is typically uncountable and the corresponding Hausdorff dimensions of these sets have been heavily investigated for a variety of models including the directed landscape, Liouville quantum gravity and the Brownian map. In this paper, we consider the directed landscape -- the scaling limit of last passage percolation as constructed in the work Dauvergne-Ortmann-Virág '18 -- and look into the Hausdorff dimension of the set of atypical stars lying on a geodesic. We show that the above dimension is almost surely equal to $1/3$. This is in contrast to Ganguly-Zhang '22, where it was shown that set of atypical stars on the line $\{x=0\}$ has dimension $2/3$. This reduction of the dimension from $2/3$ to $1/3$ yields a quantitative manifestation of the smoothing of the environment around a geodesic with regard to exceptional behaviour.
format Preprint
id arxiv_https___arxiv_org_abs_2211_05734
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Atypical stars on a directed landscape geodesic
Bhatia, Manan
Probability
In random geometry, a recurring theme is that any two geodesics emanating from a typical point part ways at a strictly positive distance from the above point, and we call such points as $1$-stars. However, the measure zero set of atypical stars, the points where such coalescence fails, is typically uncountable and the corresponding Hausdorff dimensions of these sets have been heavily investigated for a variety of models including the directed landscape, Liouville quantum gravity and the Brownian map. In this paper, we consider the directed landscape -- the scaling limit of last passage percolation as constructed in the work Dauvergne-Ortmann-Virág '18 -- and look into the Hausdorff dimension of the set of atypical stars lying on a geodesic. We show that the above dimension is almost surely equal to $1/3$. This is in contrast to Ganguly-Zhang '22, where it was shown that set of atypical stars on the line $\{x=0\}$ has dimension $2/3$. This reduction of the dimension from $2/3$ to $1/3$ yields a quantitative manifestation of the smoothing of the environment around a geodesic with regard to exceptional behaviour.
title Atypical stars on a directed landscape geodesic
topic Probability
url https://arxiv.org/abs/2211.05734