Yurinskii's Coupling for Martingales

Fuente: arXiv
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Main Authors: Cattaneo, Matias D., Masini, Ricardo P., Underwood, William G.
Format: Preprint
Published: 2022
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author Cattaneo, Matias D.
Masini, Ricardo P.
Underwood, William G.
author_facet Cattaneo, Matias D.
Masini, Ricardo P.
Underwood, William G.
contents Yurinskii's coupling is a popular theoretical tool for non-asymptotic distributional analysis in mathematical statistics and applied probability, offering a Gaussian strong approximation with an explicit error bound under easily verifiable conditions. Originally stated in $\ell_2$-norm for sums of independent random vectors, it has recently been extended both to the $\ell_p$-norm, for $1 \leq p \leq \infty$, and to vector-valued martingales in $\ell_2$-norm, under some strong conditions. We present as our main result a Yurinskii coupling for approximate martingales in $\ell_p$-norm, under substantially weaker conditions than those previously imposed. Our formulation further allows for the coupling variable to follow a more general Gaussian mixture distribution, and we provide a novel third-order coupling method which gives tighter approximations in certain settings. We specialize our main result to mixingales, martingales, and independent data, and derive uniform Gaussian mixture strong approximations for martingale empirical processes. Applications to nonparametric partitioning-based and local polynomial regression procedures are provided, alongside central limit theorems for high-dimensional martingale vectors.
format Preprint
id arxiv_https___arxiv_org_abs_2210_00362
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Yurinskii's Coupling for Martingales
Cattaneo, Matias D.
Masini, Ricardo P.
Underwood, William G.
Statistics Theory
Econometrics
Methodology
62E20, 62G20, 60G42
Yurinskii's coupling is a popular theoretical tool for non-asymptotic distributional analysis in mathematical statistics and applied probability, offering a Gaussian strong approximation with an explicit error bound under easily verifiable conditions. Originally stated in $\ell_2$-norm for sums of independent random vectors, it has recently been extended both to the $\ell_p$-norm, for $1 \leq p \leq \infty$, and to vector-valued martingales in $\ell_2$-norm, under some strong conditions. We present as our main result a Yurinskii coupling for approximate martingales in $\ell_p$-norm, under substantially weaker conditions than those previously imposed. Our formulation further allows for the coupling variable to follow a more general Gaussian mixture distribution, and we provide a novel third-order coupling method which gives tighter approximations in certain settings. We specialize our main result to mixingales, martingales, and independent data, and derive uniform Gaussian mixture strong approximations for martingale empirical processes. Applications to nonparametric partitioning-based and local polynomial regression procedures are provided, alongside central limit theorems for high-dimensional martingale vectors.
title Yurinskii's Coupling for Martingales
topic Statistics Theory
Econometrics
Methodology
62E20, 62G20, 60G42
url https://arxiv.org/abs/2210.00362