{ "id": "1607.07636", "version": "v1", "published": "2016-07-26T10:53:46.000Z", "updated": "2016-07-26T10:53:46.000Z", "title": "Asymptotics for the Time of Ruin in the War of Attrition", "authors": [ "Philip Ernst", "Ilie Grigorescu" ], "comment": "31 pages", "categories": [ "math.PR" ], "abstract": "We consider two players, starting with $m$ and $n$ units, respectively. In each round, the winner is decided with probability proportional to each player's fortune, and the opponent loses one unit. We prove an explicit formula for the probability $p(m,n)$ that the first player wins. When $m\\sim Nx_{0}$, $n\\sim N y_{0}$, we prove the fluid limit as $N\\to \\infty$. When $x_{0}=y_{0}$, then $z\\to p(N,N+z\\sqrt{N})$ converges to the standard normal CDF and the difference in fortunes scales diffusively. The exact limit of the time of ruin $\\tau_{N}$ is established as $(T-\\tau_N) \\sim N^{-\\beta}W^{\\frac{1}{\\beta}}$, $\\beta=\\frac{1}{4}$, $T=x_{0}+y_{0}$. Modulo a constant, $W \\sim \\chi^{2}_{1}(z_{0}^{2}/T^{2})$.", "revisions": [ { "version": "v1", "updated": "2016-07-26T10:53:46.000Z" } ], "analyses": { "subjects": [ "60G40", "91A60", "60C05" ], "keywords": [ "asymptotics", "standard normal cdf", "first player wins", "probability proportional", "opponent loses" ], "note": { "typesetting": "TeX", "pages": 31, "language": "en", "license": "arXiv", "status": "editable" } } }