Asymptotic considerations in a Bayesian linear model with nonparametrically modelled time series innovations

Fuente: arXiv
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Hauptverfasser: Kirch, Claudia, Meier, Alexander, Meyer, Renate, Tang, Yifu
Format: Preprint
Veröffentlicht: 2024
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author Kirch, Claudia
Meier, Alexander
Meyer, Renate
Tang, Yifu
author_facet Kirch, Claudia
Meier, Alexander
Meyer, Renate
Tang, Yifu
contents This paper considers a semiparametric approach within the general Bayesian linear model where the innovations consist of a stationary, mean zero Gaussian time series. While a parametric prior is specified for the linear model coefficients, the autocovariance structure of the time series is modeled nonparametrically using a Bernstein-Gamma process prior for the spectral density function, the Fourier transform of the autocovariance function. When updating this joint prior with Whittle's likelihood, a Bernstein-von-Mises result is established for the linear model coefficients showing the asymptotic equivalence of the corresponding estimators to those obtained from frequentist pseudo-maximum-likelihood estimation under the Whittle likelihood. Local asymptotic normality of the likelihood is shown, demonstrating that the marginal posterior distribution of the linear model coefficients shrinks at parametric rate towards the true value, and that the conditional posterior distribution of the spectral density contracts in the sup-norm, even in the case of a partially misspecified linear model.
format Preprint
id arxiv_https___arxiv_org_abs_2409_16207
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Asymptotic considerations in a Bayesian linear model with nonparametrically modelled time series innovations
Kirch, Claudia
Meier, Alexander
Meyer, Renate
Tang, Yifu
Statistics Theory
62M10, 62G86, 62F15
This paper considers a semiparametric approach within the general Bayesian linear model where the innovations consist of a stationary, mean zero Gaussian time series. While a parametric prior is specified for the linear model coefficients, the autocovariance structure of the time series is modeled nonparametrically using a Bernstein-Gamma process prior for the spectral density function, the Fourier transform of the autocovariance function. When updating this joint prior with Whittle's likelihood, a Bernstein-von-Mises result is established for the linear model coefficients showing the asymptotic equivalence of the corresponding estimators to those obtained from frequentist pseudo-maximum-likelihood estimation under the Whittle likelihood. Local asymptotic normality of the likelihood is shown, demonstrating that the marginal posterior distribution of the linear model coefficients shrinks at parametric rate towards the true value, and that the conditional posterior distribution of the spectral density contracts in the sup-norm, even in the case of a partially misspecified linear model.
title Asymptotic considerations in a Bayesian linear model with nonparametrically modelled time series innovations
topic Statistics Theory
62M10, 62G86, 62F15
url https://arxiv.org/abs/2409.16207