English

Invariance of Brownian motion associated with past and future maxima

Probability 2025-05-22 v4

Abstract

Let B={Bt}t0B=\{ B_{t}\} _{t\ge 0} be a one-dimensional standard Brownian motion. As an application of a recent result of ours on exponential functionals of Brownian motion, we show in this paper that, for every fixed t>0t>0, the process given by \begin{align*} B_{s}-B_{t}-\Bigl| B_{t}+\max _{0\le u\le s}B_{u}-\max _{s\le u\le t}B_{u} \Bigr| +\Bigl| \max _{0\le u\le s}B_{u}-\max _{s\le u\le t}B_{u} \Bigr| ,\quad 0\le s\le t, \end{align*} is a Brownian motion. The path transformation that describes the above process is proven to be an involution, commute with time reversal, and preserve Pitman's transformation. A connection with Pitman's 2MX2M-X theorem is also discussed.

Keywords

Cite

@article{arxiv.2303.09163,
  title  = {Invariance of Brownian motion associated with past and future maxima},
  author = {Yuu Hariya},
  journal= {arXiv preprint arXiv:2303.09163},
  year   = {2025}
}

Comments

22 pages. This is the version accepted for publication in the journal of Stochastics on May 20, 2025; minor modifications have been made from the previous version