Gambler’s Ruin: A Random Walk on the Simplex
Gambler’s Ruin: A Random Walk on the Simplex
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赌徒的毁灭:单纯形上的随机游走
DOI:
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发表时间:
1987
期刊:
影响因子:
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通讯作者:
B. Hajek
中科院分区:
文献类型:
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作者:
B. Hajek
The purpose of this note is to give a solution to a problem of Thomas M. Cover (see Chapter V, Section 5.4). Suppose there are three gamblers with respective capital p a , p b , and p c , where p a + p b + p c = 1. The players engage in a symmetric three-way game modeled by Brownian motion in the two-dimensional simplex P i ≥ 0, p a + p b + p c = 1. When one of the players goes broke, play continues between the remaining two players, where the play is now modeled by a Brownian motion in one dimension, until a second player loses, and the remaining player is declared a winner. Doob’s optional sampling theorem implies that player i will be a winner with probability p i . Cover’s problem is to find the probability that the players lose in a specific order. For example, we would like to find the probability that player 3 loses first and then player 2 loses. We provide a “messy” solution.