A Spectral Representation of a Class of Nonstationary Processes
In this paper, an extension of the weakly harmonizable class of processes is considered. This class, termed almost periodic contractive harmonizable, is based upon the natural contractive operator associated with harmonizable processes. A spectral representation of these processes is obtained. A relation between the almost periodic contractive harmonizable and the oscillatory harmonizable classes is considered. The paper concludes with a series representation for the almost periodic contractive harmonizable class.
AMS Subject Classification60G12 60G35
KeywordsHarmonizable processes Oscillatory processes Semi-groups of contractive operators Almost periodic functions
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