论文标题

在投影强大的最佳运输方面:样品复杂性和模型错误指定

On Projection Robust Optimal Transport: Sample Complexity and Model Misspecification

论文作者

Lin, Tianyi, Zheng, Zeyu, Chen, Elynn Y., Cuturi, Marco, Jordan, Michael I.

论文摘要

最佳运输(OT)距离越来越多地用作统计推断的损失函数,特别是在学习生成模型或监督学习中。然而,最小瓦斯汀估计量的行为知之甚少,尤其是在高维状态下或模型错误指定。在这项工作中,我们采用了预测鲁棒(PR)OT的观点,该观点旨在通过选择可以预测的$ k $维二维子空间来最大化两种措施之间的OT成本。我们的第一个贡献是建立PR Wasserstein距离的几种基本统计特性,以补充和改善以前的文献,这些文献仅限于一维且指定良好的病例。接下来,我们通过平均而不是优化子空间来提出整体PR Wasserstein(IPRW)距离作为PRW距离的替代方案。我们的复杂性界限可以帮助解释为什么PRW和IPRW距离在高维推理任务中以经验上的距离优于Wasserstein距离。最后,我们考虑使用PRW距离进行参数推断。我们提供了两种最小PRW估计量的渐近保证,并在模型错误指定下为Max-Sined Wasestein估计量制定了中心极限定理。为了使我们对PRW的分析具有大于一个大于一个的投影维度,我们设计了变分分析和统计理论的新型组合。

Optimal transport (OT) distances are increasingly used as loss functions for statistical inference, notably in the learning of generative models or supervised learning. Yet, the behavior of minimum Wasserstein estimators is poorly understood, notably in high-dimensional regimes or under model misspecification. In this work we adopt the viewpoint of projection robust (PR) OT, which seeks to maximize the OT cost between two measures by choosing a $k$-dimensional subspace onto which they can be projected. Our first contribution is to establish several fundamental statistical properties of PR Wasserstein distances, complementing and improving previous literature that has been restricted to one-dimensional and well-specified cases. Next, we propose the integral PR Wasserstein (IPRW) distance as an alternative to the PRW distance, by averaging rather than optimizing on subspaces. Our complexity bounds can help explain why both PRW and IPRW distances outperform Wasserstein distances empirically in high-dimensional inference tasks. Finally, we consider parametric inference using the PRW distance. We provide an asymptotic guarantee of two types of minimum PRW estimators and formulate a central limit theorem for max-sliced Wasserstein estimator under model misspecification. To enable our analysis on PRW with projection dimension larger than one, we devise a novel combination of variational analysis and statistical theory.

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