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The behaviour of the likelihood function for ARMA models

Published online by Cambridge University Press:  01 July 2016

M. Deistler*
Affiliation:
University of Technology, Vienna
B. M. Pötscher*
Affiliation:
University of Technology, Vienna
*
Postal address: Institute of Econometrics and Operations Research, University of Technology, A-1040 Vienna, Argentinierstr. 8, Austria.
Postal address: Institute of Econometrics and Operations Research, University of Technology, A-1040 Vienna, Argentinierstr. 8, Austria.

Abstract

The paper deals with some properties of the (Gaussian) likelihood function for multivariable ARMA models. Its behaviour at the boundary of the parameter space is described; its continuity properties as well as the question of the existence of a maximum are discussed. We have not been able to show in general the existence of the maximum over the usual parameter spaces. However, the maximum always exists over a suitably enlarged parameter space (given that the data are non-degenerate), which includes parameters corresponding to processes with discrete spectral components.

Type
Research Article
Copyright
Copyright © Applied Probability Trust 1984 

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Footnotes

Support by ‘Fonds zur Förderung der wissenschaftlichen Forschung', project No. 4393, is gratefully acknowledged.

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