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The discrete-stable distributions are a class of probability distributions with the property that the sum of several random variables from such a distribution is distributed according to the same family. They are the discrete analogue of the continuous-stable distributions. The discrete-stable distributions have been used in numerous fields, in particular in scale-free networks such as the internet, social networks〔Barabási, Albert-László (2003). Linked: how everything is connected to everything else and what it means for business, science, and everyday life. New York, NY: Plum.〕 or even semantic networks Both classes of distribution have properties such as infinitely divisibility, power law tails and unimodality. The most well-known discrete stable distribution is the Poisson distribution which is a special case as the only discrete-stable distribution for which the mean and all higher-order moments are finite. == Definition == The discrete-stable distributions are defined through their probability-generating function : In the above, is a scale parameter and describes the power-law behaviour such that when , : A closed-form expression using elementary functions for the probability distribution of the discrete-stable distributions is not known except for in the Poisson case, in which : Expressions do exist, however, using special functions for the case (in terms of Bessel functions) and (in terms of hypergeometric functions). 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Discrete-stable distribution」の詳細全文を読む スポンサード リンク
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