{ "id": "0807.4072", "version": "v2", "published": "2008-07-25T11:35:54.000Z", "updated": "2008-09-17T09:04:59.000Z", "title": "Sylvester's question and the Random Acceleration Process", "authors": [ "H. J. Hilhorst", "P. Calka", "G. Schehr" ], "comment": "29 pages, 4 figures; references added and minor changes", "journal": "J. Stat. Mech. (2008) P10010", "doi": "10.1088/1742-5468/2008/10/P10010", "categories": [ "cond-mat.stat-mech" ], "abstract": "Let n points be chosen randomly and independently in the unit disk. \"Sylvester's question\" concerns the probability p_n that they are the vertices of a convex n-sided polygon. Here we establish the link with another problem. We show that for large n this polygon, when suitably parametrized by a function r(phi) of the polar angle phi, satisfies the equation of the random acceleration process (RAP), d^2 r/d phi^2 = f(phi), where f is Gaussian noise. On the basis of this relation we derive the asymptotic expansion log p_n = -2n log n + n log(2 pi^2 e^2) - c_0 n^{1/5} + ..., of which the first two terms agree with a rigorous result due to Barany. The nonanalyticity in n of the third term is a new result. The value 1/5 of the exponent follows from recent work on the RAP due to Gyorgyi et al. [Phys. Rev. E 75, 021123 (2007)]. We show that the n-sided polygon is effectively contained in an annulus of width \\sim n^{-4/5} along the edge of the disk. The distance delta_n of closest approach to the edge is exponentially distributed with average 1/(2n).", "revisions": [ { "version": "v2", "updated": "2008-09-17T09:04:59.000Z" } ], "analyses": { "keywords": [ "random acceleration process", "sylvesters question", "polar angle phi", "asymptotic expansion log", "convex n-sided polygon" ], "tags": [ "journal article" ], "publication": { "journal": "Journal of Statistical Mechanics: Theory and Experiment", "year": 2008, "month": "Oct", "volume": 2008, "number": 10, "pages": 10010 }, "note": { "typesetting": "TeX", "pages": 29, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008JSMTE..10..010H" } } }