Equicontinuous families of operators generating mean periodic maps
Valentina Casarino · PORTO Publications Open Repository TOrino (Politecnico di Torino) · 1999
The existence of mean periodic functions in the sense of L. Schwartz, generated, in various ways, by an equicontinuous group U or an equicontinuous cosine function C forces the spectral structure of the infinitesimal generator of U or C. In particular, it is proved under fairly general hypotheses that the spectrum has no accumulation point and that the continuous spectrum is empty.