English

How round are the complementary components of planar Brownian motion?

Probability 2021-11-02 v1

Abstract

Consider a Brownian motion WW in C{\bf C} started from 00 and run for time 1. Let A(1),A(2),A(1),A(2),\dots denote the bounded connected components of CW([0,1]){\bf C}-W([0,1]). Let R(i)R(i) (resp. r(i)r(i)) denote the out-radius (resp. in-radius) of A(i)A(i) for iNi\in\bf N. Our main result is that E[iR(i)2logR(i)θ]<{\bf E}[\sum_i R(i)^2|\log R(i)|^\theta ]<\infty for any θ<1\theta<1. We also prove that ir(i)2logr(i)=\sum_i r(i)^2|\log r(i)|=\infty almost surely. These results have the interpretation that most of the components A(i)A(i) have a rather regular or round shape.

Keywords

Cite

@article{arxiv.1609.06627,
  title  = {How round are the complementary components of planar Brownian motion?},
  author = {Nina Holden and Serban Nacu and Yuval Peres and Thomas S. Salisbury},
  journal= {arXiv preprint arXiv:1609.06627},
  year   = {2021}
}

Comments

28 pages, 11 figures

R2 v1 2026-06-22T15:56:49.763Z