Spectra of stationary processes on Z
50 Years with Hardy Spaces, A Tribute to Victor Havin (eds. A.Baranov, S.Kisliakov, N.Nikolski), Operator Theory: Advances and Applications, vol. 261, 2018, 141-157
Résumé
We will discuss a somewhat striking spectral property of finitely valued stationary processes on Z that says that if the spectral measure of the process has a gap then the process is periodic. We will give some extensions of this result and raise several related questions.