Convergence rates for estimating multivariate scale mixtures of uniform densities

Fuente: arXiv
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Main Authors: Kim, Arlene K. H., Kur, Gil, Guntuboyina, Adityanand
Format: Preprint
Published: 2024
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author Kim, Arlene K. H.
Kur, Gil
Guntuboyina, Adityanand
author_facet Kim, Arlene K. H.
Kur, Gil
Guntuboyina, Adityanand
contents The Grenander estimator is a well-studied procedure for univariate nonparametric density estimation. It is usually defined as the Maximum Likelihood Estimator (MLE) over the class of all non-increasing densities on the positive real line. It can also be seen as the MLE over the class of all scale mixtures of uniform densities. Using the latter viewpoint, Pavlides and Wellner~\cite{pavlides2012nonparametric} proposed a multivariate extension of the Grenander estimator as the nonparametric MLE over the class of all multivariate scale mixtures of uniform densities. We prove that this multivariate estimator achieves the univariate cube root rate of convergence with only a logarithmic multiplicative factor that depends on the dimension. The usual curse of dimensionality is therefore avoided to some extent for this multivariate estimator. This result positively resolves a conjecture of Pavlides and Wellner~\cite{pavlides2012nonparametric} under an additional lower bound assumption. Our proof proceeds via a general accuracy result for the Hellinger accuracy of MLEs over convex classes of densities. We also provide algorithms for computing the estimator, and illustrate performance on real and simulated datasets.
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id arxiv_https___arxiv_org_abs_2410_10251
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Convergence rates for estimating multivariate scale mixtures of uniform densities
Kim, Arlene K. H.
Kur, Gil
Guntuboyina, Adityanand
Statistics Theory
The Grenander estimator is a well-studied procedure for univariate nonparametric density estimation. It is usually defined as the Maximum Likelihood Estimator (MLE) over the class of all non-increasing densities on the positive real line. It can also be seen as the MLE over the class of all scale mixtures of uniform densities. Using the latter viewpoint, Pavlides and Wellner~\cite{pavlides2012nonparametric} proposed a multivariate extension of the Grenander estimator as the nonparametric MLE over the class of all multivariate scale mixtures of uniform densities. We prove that this multivariate estimator achieves the univariate cube root rate of convergence with only a logarithmic multiplicative factor that depends on the dimension. The usual curse of dimensionality is therefore avoided to some extent for this multivariate estimator. This result positively resolves a conjecture of Pavlides and Wellner~\cite{pavlides2012nonparametric} under an additional lower bound assumption. Our proof proceeds via a general accuracy result for the Hellinger accuracy of MLEs over convex classes of densities. We also provide algorithms for computing the estimator, and illustrate performance on real and simulated datasets.
title Convergence rates for estimating multivariate scale mixtures of uniform densities
topic Statistics Theory
url https://arxiv.org/abs/2410.10251