Distances on random probability measures

Catalano Marta, Luiss University

Random probabilities are a key component to many nonparametric methods in Statistics and Machine Learning. To quantify comparisons between different laws of random probabilities several works are starting to use the elegant Wasserstein over Wasserstein distance. In this talk we show that the infinite-dimensionality of the space of probabilities drastically deteriorates its sample complexity, which is slower than any polynomial rate in the sample size. We thus propose a new distance that preserves many desirable properties of the former while achieving a parametric rate of convergence. In particular, our distance 1) metrizes weak convergence; 2) can be estimated numerically through samples with low complexity; 3) can be bounded analytically from above and below. The main ingredient are integral probability metrics, which lead to the name hierarchical IPM. This is joint work with Hugo Lavenant.

Area: IS2 - Dependence structures in Bayesian nonparametrics (Federico Camerlenghi)

Keywords: Bayesian nonparametric statistics, Optimal transport, Wasserstein distance,

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