Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time Series

The aim of this paper to give a multidimensional version of the classical one-dimensional case of smooth spectral density. A spectral density with smooth eigenvalues and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics>...

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Main Author: Tamás Szabados
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Econometrics
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Online Access:https://www.mdpi.com/2225-1146/11/2/14
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author Tamás Szabados
author_facet Tamás Szabados
author_sort Tamás Szabados
collection DOAJ
description The aim of this paper to give a multidimensional version of the classical one-dimensional case of smooth spectral density. A spectral density with smooth eigenvalues and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>H</mi><mo>∞</mo></msup></semantics></math></inline-formula> eigenvectors gives an explicit method to factorize the spectral density and compute the Wold representation of a weakly stationary time series. A formula, similar to the Kolmogorov–Szeg<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mover><mi mathvariant="normal">o</mi><mo>”</mo></mover></mrow></semantics></math></inline-formula> formula, is given for the covariance matrix of the innovations. These results are important to give the best linear predictions of the time series. The results are applicable when the rank of the process is smaller than the dimension of the process, which occurs frequently in many current applications, including econometrics.
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spelling doaj.art-dfe0b42353424c04be36a0812e2fba702023-11-18T10:05:17ZengMDPI AGEconometrics2225-11462023-05-011121410.3390/econometrics11020014Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time SeriesTamás Szabados0Department of Mathematics, Budapest University of Technology and Economics, 1111 Budapest, HungaryThe aim of this paper to give a multidimensional version of the classical one-dimensional case of smooth spectral density. A spectral density with smooth eigenvalues and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>H</mi><mo>∞</mo></msup></semantics></math></inline-formula> eigenvectors gives an explicit method to factorize the spectral density and compute the Wold representation of a weakly stationary time series. A formula, similar to the Kolmogorov–Szeg<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mover><mi mathvariant="normal">o</mi><mo>”</mo></mover></mrow></semantics></math></inline-formula> formula, is given for the covariance matrix of the innovations. These results are important to give the best linear predictions of the time series. The results are applicable when the rank of the process is smaller than the dimension of the process, which occurs frequently in many current applications, including econometrics.https://www.mdpi.com/2225-1146/11/2/14multidimensional stationary time seriessmooth spectral densityspectral factorbest linear prediction
spellingShingle Tamás Szabados
Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time Series
Econometrics
multidimensional stationary time series
smooth spectral density
spectral factor
best linear prediction
title Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time Series
title_full Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time Series
title_fullStr Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time Series
title_full_unstemmed Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time Series
title_short Factorization of a Spectral Density with Smooth Eigenvalues of a Multidimensional Stationary Time Series
title_sort factorization of a spectral density with smooth eigenvalues of a multidimensional stationary time series
topic multidimensional stationary time series
smooth spectral density
spectral factor
best linear prediction
url https://www.mdpi.com/2225-1146/11/2/14
work_keys_str_mv AT tamasszabados factorizationofaspectraldensitywithsmootheigenvaluesofamultidimensionalstationarytimeseries