{ "id": "1301.4059", "version": "v1", "published": "2013-01-17T11:48:33.000Z", "updated": "2013-01-17T11:48:33.000Z", "title": "Convex hulls of planar random walks with drift", "authors": [ "Andrew R. Wade", "Chang Xu" ], "comment": "13 pages, 3 figures", "categories": [ "math.PR" ], "abstract": "Denote by $L_n$ the length of the perimeter of the convex hull of $n$ steps of a planar random walk whose increments have finite second moment and non-zero mean. Snyder and Steele showed that $n^{-1} L_n$ converges almost surely to a deterministic limit, and proved an upper bound on the variance $Var [ L_n] = O(n)$. We show that $n^{-1} Var [L_n]$ converges and give a simple expression for the limit, which is non-zero for walks outside a certain degenerate class. This answers a question of Snyder and Steele. Furthermore, we prove a central limit theorem for $L_n$ in the non-degenerate case.", "revisions": [ { "version": "v1", "updated": "2013-01-17T11:48:33.000Z" } ], "analyses": { "subjects": [ "60G50", "60D05", "60J10", "60F05" ], "keywords": [ "planar random walk", "convex hull", "central limit theorem", "finite second moment", "degenerate class" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable" } } }