{ "id": "0708.1676", "version": "v1", "published": "2007-08-13T09:48:40.000Z", "updated": "2007-08-13T09:48:40.000Z", "title": "Curve crossing for random walks reflected at their maximum", "authors": [ "Ron Doney", "Ross Maller" ], "comment": "Published at http://dx.doi.org/10.1214/009117906000000953 in the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org)", "journal": "Annals of Probability 2007, Vol. 35, No. 4, 1351-1373", "doi": "10.1214/009117906000000953", "categories": [ "math.PR" ], "abstract": "Let $R_n=\\max_{0\\leq j\\leq n}S_j-S_n$ be a random walk $S_n$ reflected in its maximum. Except in the trivial case when $P(X\\ge0)=1$, $R_n$ will pass over a horizontal boundary of any height in a finite time, with probability 1. We extend this by giving necessary and sufficient conditions for finiteness of passage times of $R_n$ above certain curved (power law) boundaries, as well. The intuition that a degree of heaviness of the negative tail of the distribution of the increments of $S_n$ is necessary for passage of $R_n$ above a high level is correct in most, but not all, cases, as we show. Conditions are also given for the finiteness of the expected passage time of $R_n$ above linear and square root boundaries.", "revisions": [ { "version": "v1", "updated": "2007-08-13T09:48:40.000Z" } ], "analyses": { "subjects": [ "60J15", "60F15", "60K05", "60G40", "60F05", "60G42" ], "keywords": [ "random walks", "curve crossing", "square root boundaries", "horizontal boundary", "expected passage time" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0708.1676D" } } }