A contribution to the study of periodic systems in the behavioral approach

In this paper we obtain new results on periodic kernel representations and propose a definition of “image" representation for periodic behaviors. Further, we characterize controllability and autonomicity in representation terms. We also show that the concept of free variable used in the time-invariant case cannot be carried over to the periodic case in a straightforward manner and introduce a new concept of variable freeness (P-periodic freeness). This allows us to define input/output structures for periodic behaviors