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On the edge eigenvalues of the precision matrices of nonstationary autoregressive processes

Published online by Cambridge University Press:  27 May 2025

Junho Yang*
Affiliation:
Academia Sinica
*
*Postal address: Institute of Statistical Science, No.128, Academia Rd., Sect. 2, Taipei 115, Taiwan. Email: junhoyang@stat.sinica.edu.tw

Abstract

This paper investigates structural changes in the parameters of first-order autoregressive (AR) models by analyzing the edge eigenvalues of the precision matrices. Specifically, edge eigenvalues in the precision matrix are observed if and only if there is a structural change in the AR coefficients. We show that these edge eigenvalues correspond to the zeros of a determinantal equation. Additionally, we propose a consistent estimator for detecting outliers within the panel time series framework, supported by numerical experiments.

Type
Original Article
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Applied Probability Trust

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