{ "id": "2105.11042", "version": "v1", "published": "2021-05-23T23:24:59.000Z", "updated": "2021-05-23T23:24:59.000Z", "title": "Markovian structure in the concave majorant of Brownian motion", "authors": [ "Mehdi Ouaki", "Jim Pitman" ], "comment": "24 pages", "categories": [ "math.PR" ], "abstract": "The purpose of this paper is to highlight some hidden Markovian structure of the concave majorant of the Brownian motion. Several distributional identities are implied by the joint law of a standard one-dimensional Brownian motion $B$ and its almost surely unique concave majorant $K$ on $[0,\\infty)$. In particular, the one-dimensional distribution of $2 K_t - B_t$ is that of $R_5(t)$, where $R_5$ is a $5-$dimensional Bessel process with $R_5(0) = 0$. The process $2K-B$ shares a number of other properties with $R_5$, and we conjecture that it may have the distribution of $R_5$. We also describe the distribution of the convex minorant of a three-dimensional Bessel process with drift.", "revisions": [ { "version": "v1", "updated": "2021-05-23T23:24:59.000Z" } ], "analyses": { "subjects": [ "60G51", "60G55", "60J65" ], "keywords": [ "standard one-dimensional brownian motion", "three-dimensional bessel process", "distribution", "surely unique concave majorant", "hidden markovian structure" ], "note": { "typesetting": "TeX", "pages": 24, "language": "en", "license": "arXiv", "status": "editable" } } }