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arXiv 2109.06646math.STmath.PRstat.TH
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随机测度的Wasserstein依赖性指数

A Wasserstein index of dependence for random measures

Marta Catalano, Hugo Lavenant, Antonio Lijoi, Igor Prünster

AI总结:

本文开创性地利用Lévy测度间的最优传输距离,提出首个针对完全随机测度且考虑其无限维分布的[0,1]依赖性指数,揭示了模型深层结构并支持贝叶斯非参数模型的先验规范与公平比较。

摘要:

最优传输和Wasserstein距离在许多科学领域中正蓬勃发展,作为比较和连接随机结构的手段。在这里,我们开创性地使用Lévy测度之间的最优传输距离来解决一个统计问题。依赖性贝叶斯非参数模型为不同但相关的观察组提供了灵活的推断。随机测度向量的每个分量对一组可交换观测进行建模,而它们之间的依赖性则调节了跨组的信息借用。我们推导出了针对(完全)随机测度的首个在[0,1]区间内的统计依赖性指数,该指数考虑了其整个无限维分布,并假设该分布在不同的组之间是相等的。这是通过利用Wasserstein距离的几何特性,在底层的Lévy测度层面上解决一个极大极小问题来实现的。该Wasserstein依赖性指数揭示了模型的深层结构,并具有以下理想特性:(i) 当且仅当随机测度相互独立时,其值为0;(ii) 当且仅当随机测度完全依赖时,其值为1;(iii) 它同时量化了d ≥ 2个随机测度的依赖性,避免了成对比较的需要;(iv) 它可以进行数值评估。此外,该指数允许为贝叶斯非参数模型进行有信息的先验规范和公平的模型比较。

英文摘要:

Optimal transport and Wasserstein distances are flourishing in many scientific fields as a means for comparing and connecting random structures. Here we pioneer the use of an optimal transport distance between Lévy measures to solve a statistical problem. Dependent Bayesian nonparametric models provide flexible inference on distinct, yet related, groups of observations. Each component of a vector of random measures models a group of exchangeable observations, while their dependence regulates the borrowing of information across groups. We derive the first statistical index of dependence in $[0,1]$ for (completely) random measures that accounts for their whole infinite-dimensional distribution, which is assumed to be equal across different groups. This is accomplished by using the geometric properties of the Wasserstein distance to solve a max-min problem at the level of the underlying Lévy measures. The Wasserstein index of dependence sheds light on the models' deep structure and has desirable properties: (i) it is $0$ if and only if the random measures are independent; (ii) it is $1$ if and only if the random measures are completely dependent; (iii) it simultaneously quantifies the dependence of $d \ge 2$ random measures, avoiding the need for pairwise comparisons; (iv) it can be evaluated numerically. Moreover, the index allows for informed prior specifications and fair model comparisons for Bayesian nonparametric models.

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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