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arXiv 2004.05542math.STmath.PRstat.TH
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观测可交换序列潜结构模型中de Finetti混合测度的收敛性

Convergence of de Finetti's mixing measure in latent structure models for observed exchangeable sequences

Yun Wei, XuanLong Nguyen

摘要:

产品分布的混合是了解数据群体内异质性的强大工具。在这类潜在结构模型中,de Finetti的混合测度对于描述代表异质性的潜在参数的不确定性起着核心作用。本文在观测变量可交换序列数目增加而序列长度固定或可变的情况下,建立了乘积分布有限混合的de Finetti混合测度的后验压缩定理。我们将仔细研究序列数目和序列长度的作用。为了得到具体的收敛速度,有限混合模型的一阶可识别性理论和一族尖锐的逆界的混合产品分布将开发通过调和分析这样的潜在结构模型。该理论适用于构成连续域和离散域$\mathfrak{X}$的乘积分布的混合模型的广泛类的概率核。感兴趣的例子包括概率核在Ho和Nguyen(2016)的意义上仅弱可识别的情况,核本身是分层模型中的混合分布的情况,以及核可能不具有关于抽象域$\mathfrak{X}$(如Dirichlet过程)上的支配测度的密度的情况。

英文摘要:

Mixtures of product distributions are a powerful device for learning about heterogeneity within data populations. In this class of latent structure models, de Finetti's mixing measure plays the central role for describing the uncertainty about the latent parameters representing heterogeneity. In this paper posterior contraction theorems for de Finetti's mixing measure arising from finite mixtures of product distributions will be established, under the setting the number of exchangeable sequences of observed variables increases while sequence length(s) may be either fixed or varied. The role of both the number of sequences and the sequence lengths will be carefully examined. In order to obtain concrete rates of convergence, a first-order identifiability theory for finite mixture models and a family of sharp inverse bounds for mixtures of product distributions will be developed via a harmonic analysis of such latent structure models. This theory is applicable to broad classes of probability kernels composing the mixture model of product distributions for both continuous and discrete domain $\mathfrak{X}$. Examples of interest include the case the probability kernel is only weakly identifiable in the sense of Ho and Nguyen (2016), the case where the kernel is itself a mixture distribution as in hierarchical models, and the case the kernel may not have a density with respect to a dominating measure on an abstract domain $\mathfrak{X}$ such as Dirichlet processes.

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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