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arXiv 2109.10481math.STcs.ITmath.ITstat.TH
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稀疏均匀性试验

Sparse Uniformity Testing

Bhaswar B. Bhattacharya, Rajarshi Mukherjee

摘要:

本文考虑高维离散分布(多项式)在稀疏选择下的一致性检验问题。更确切地说,我们得到尖锐的检测阈值测试,$n$样本的基础上,是否支持$d$元素的离散分布不同于均匀分布,只有在$s$(出的$d$)坐标,是$\varepsilon$ -远(在全变差距离)从均匀性。我们的结果揭示了各种有趣的相变,这些相变取决于样本量$n$和信号强度$\varepsilon$与维度$d$和稀疏水平$s$的相互作用。例如,如果样本量小于阈值(取决于$d$和$s$),则所有测试都是渐近无效的,而不管信号强度的大小。另一方面,如果样本量高于阈值,则检测边界根据信号强度经历进一步的相变。在这里,一个$χ^2$型测试达到检测边界的密集制度,而在稀疏制度的Bonferroni校正的两个最大型测试和一个版本的更高的批评测试是最佳的尖锐常数。这些结果结合起来提供了一个完整的描述的相位图的稀疏均匀性测试问题的所有制度的参数$n$,$d$,和$s$。处理多项式的一个挑战是参数总是被限制在单纯形中。这导致了前面提到的两层相变,这是一种在经典的高维稀疏测试问题中不会出现的新现象。

英文摘要:

In this paper we consider the uniformity testing problem for high-dimensional discrete distributions (multinomials) under sparse alternatives. More precisely, we derive sharp detection thresholds for testing, based on $n$ samples, whether a discrete distribution supported on $d$ elements differs from the uniform distribution only in $s$ (out of the $d$) coordinates and is $\varepsilon$-far (in total variation distance) from uniformity. Our results reveal various interesting phase transitions which depend on the interplay of the sample size $n$ and the signal strength $\varepsilon$ with the dimension $d$ and the sparsity level $s$. For instance, if the sample size is less than a threshold (which depends on $d$ and $s$), then all tests are asymptotically powerless, irrespective of the magnitude of the signal strength. On the other hand, if the sample size is above the threshold, then the detection boundary undergoes a further phase transition depending on the signal strength. Here, a $χ^2$-type test attains the detection boundary in the dense regime, whereas in the sparse regime a Bonferroni correction of two maximum-type tests and a version of the Higher Criticism test is optimal up to sharp constants. These results combined provide a complete description of the phase diagram for the sparse uniformity testing problem across all regimes of the parameters $n$, $d$, and $s$. One of the challenges in dealing with multinomials is that the parameters are always constrained to lie in the simplex. This results in the aforementioned two-layered phase transition, a new phenomenon which does not arise in classical high-dimensional sparse testing problems.

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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