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arXiv math/0410174math.PR
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占用问题的大偏差渐近性

Large deviation asymptotics for occupancy problems

Paul Dupuis, Carl Nuzman, Phil Whiting

摘要:

在占用问题的标准公式中,我们考虑了r个球在n个单元中的分布,每个球以1/n的概率独立地分配给给定的单元。虽然封闭形式的表达式可以给出各种有趣的量的分布(如包含给定数量的球的细胞的分数),这些表达式通常是有限的实际用途。近似提供了一个有吸引力的替代方案,在本文中,我们考虑一个大偏差近似r和n趋于无穷大。为了分析这个问题,我们首先考虑一个动力学模型,在这个模型中,球被顺序地放置在单元格中,“时间”对应于已经被抛出的球的数量。对这一"过程级"问题进行了全面的大偏差分析,然后利用收缩原理得到了原问题的速率函数。分析了表征这一速率函数的变分问题,并得到了一个相当完整的显式解。最小化轨迹和最小成本被确定为两个常数,并且常数被表征为初等不动点问题的唯一解。这些结果,然后用来解决一些有趣的问题,包括溢出问题和部分优惠券收集器的问题。

英文摘要:

In the standard formulation of the occupancy problem one considers the distribution of r balls in n cells, with each ball assigned independently to a given cell with probability 1/n. Although closed form expressions can be given for the distribution of various interesting quantities (such as the fraction of cells that contain a given number of balls), these expressions are often of limited practical use. Approximations provide an attractive alternative, and in the present paper we consider a large deviation approximation as r and n tend to infinity. In order to analyze the problem we first consider a dynamical model, where the balls are placed in the cells sequentially and ``time'' corresponds to the number of balls that have already been thrown. A complete large deviation analysis of this ``process level'' problem is carried out, and the rate function for the original problem is then obtained via the contraction principle. The variational problem that characterizes this rate function is analyzed, and a fairly complete and explicit solution is obtained. The minimizing trajectories and minimal cost are identified up to two constants, and the constants are characterized as the unique solution to an elementary fixed point problem. These results are then used to solve a number of interesting problems, including an overflow problem and the partial coupon collector's problem.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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