{ "id": "2307.10027", "version": "v1", "published": "2023-07-19T15:12:05.000Z", "updated": "2023-07-19T15:12:05.000Z", "title": "Iterated-logarithm laws for convex hulls of random walks with drift", "authors": [ "Wojciech Cygan", "Nikola Sandrić", "Stjepan Šebek", "Andrew Wade" ], "comment": "27 pages, 2 figures", "categories": [ "math.PR" ], "abstract": "We establish laws of the iterated logarithm for intrinsic volumes of the convex hull of many-step, multidimensional random walks whose increments have two moments and a non-zero drift. Analogous results in the case of zero drift, where the scaling is different, were obtained by Khoshnevisan. Our starting point is a version of Strassen's functional law of the iterated logarithm for random walks with drift. For the special case of the area of a planar random walk with drift, we compute explicitly the constant in the iterated-logarithm law by solving an isoperimetric problem reminiscent of the classical Dido problem. For general intrinsic volumes and dimensions, our proof exploits a novel zero--one law for functionals of convex hulls of walks with drift, of some independent interest. As another application of our approach, we obtain iterated-logarithm laws for intrinsic volumes of the convex hull of the centre of mass (running average) process associated to the random walk.", "revisions": [ { "version": "v1", "updated": "2023-07-19T15:12:05.000Z" } ], "analyses": { "subjects": [ "60G50", "60D05", "60F15", "60J65", "52A22" ], "keywords": [ "convex hull", "iterated-logarithm law", "strassens functional law", "multidimensional random walks", "planar random walk" ], "note": { "typesetting": "TeX", "pages": 27, "language": "en", "license": "arXiv", "status": "editable" } } }