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arXiv 0704.0918math.AGmath.STstat.TH
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高斯贝叶斯网络的Algebraic geometry

Algebraic geometry of Gaussian Bayesian networks

Seth Sullivant

摘要:

高斯情形下的条件独立模型是正定协方差阵锥上的代数簇。我们研究这些品种的情况下,贝叶斯网络,以期推广递归因式分解定理的情况下,隐藏变量。在底层图是树的情况下,我们证明了模型的消失理想是由图所隐含的条件独立语句所生成的。我们还表明,理想的任何贝叶斯网络是均匀的,相对于一个多级诱导的上游随机变量的集合。这对隐变量模型有许多重要的影响。最后,我们将贝叶斯网络的理想与代数几何中的一些经典结构联系起来,包括格拉斯曼曲面退化、矩阵舒伯特簇和割线簇。

英文摘要:

Conditional independence models in the Gaussian case are algebraic varieties in the cone of positive definite covariance matrices. We study these varieties in the case of Bayesian networks, with a view towards generalizing the recursive factorization theorem to situations with hidden variables. In the case when the underlying graph is a tree, we show that the vanishing ideal of the model is generated by the conditional independence statements implied by graph. We also show that the ideal of any Bayesian network is homogeneous with respect to a multigrading induced by a collection of upstream random variables. This has a number of important consequences for hidden variable models. Finally, we relate the ideals of Bayesian networks to a number of classical constructions in algebraic geometry including toric degenerations of the Grassmannian, matrix Schubert varieties, and secant varieties.

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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