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arXiv 2110.00295math.PR
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紧空间上的经验测度与随机游走的二次Wasserstein度量

Empirical measures and random walks on compact spaces in the quadratic Wasserstein metric

Bence Borda

AI总结:

本文扩展了2维流形上的结果,证明了d维紧Riemann流形上经验测度在二次Wasserstein度量下的精确收敛速率上界,并将i.i.d.条件放宽至混合平稳样本及紧Lie群上的随机游走,发现半单群上无需谱隙假设即可达近最优速率。

摘要:

估计i.i.d.样本的经验测度到参考测度的收敛速率是概率论中的经典问题。扩展Ambrosio、Stra和Trevisan在2维流形上的近期结果,本文证明了d维紧Riemann流形上二次Wasserstein度量$W_2$中平均速率的精确渐近和非渐近上界。在参考测度的平滑性假设下,我们的界与Ajtai、Komlós、Tusnády和Talagrand给出的单位立方体上最优匹配问题的经典速率一致。i.i.d.条件被放宽为具有混合条件的平稳样本。作为非平稳样本的例子,我们还考虑了紧Lie群上随机游走的经验测度。令人惊讶的是,在半单群上,即使没有谱隙假设,随机游走也能达到几乎最优的速率。证明基于Fourier分析,特别是基于紧流形上$W_2$的Berry-Esseen平滑不等式,这是一个具有独立意义和广泛应用范围的结果。

英文摘要:

Estimating the rate of convergence of the empirical measure of an i.i.d. sample to the reference measure is a classical problem in probability theory. Extending recent results of Ambrosio, Stra and Trevisan on 2-dimensional manifolds, in this paper we prove sharp asymptotic and nonasymptotic upper bounds for the mean rate in the quadratic Wasserstein metric $W_2$ on a $d$-dimensional compact Riemannian manifold. Under a smoothness assumption on the reference measure, our bounds match the classical rate in the optimal matching problem on the unit cube due to Ajtai, Komlós, Tusnády and Talagrand. The i.i.d. condition is relaxed to stationary samples with a mixing condition. As an example of a nonstationary sample, we also consider the empirical measure of a random walk on a compact Lie group. Surprisingly, on semisimple groups random walks attain almost optimal rates even without a spectral gap assumption. The proofs are based on Fourier analysis, and in particular on a Berry-Esseen smoothing inequality for $W_2$ on compact manifolds, a result of independent interest with a wide range of applications.

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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