Nonstationary Systems and Point Evaluation
This chapter introduces discrete time-varying input output systems, and various notions connected with them. The chapter also serves as a further motivation for the interpolation problems considered in the previous chapter. Special attention is paid to the interpretation of the nonstationary version of point evaluation. It will also be shown how one may convert a time-varying system into an infinite dimensional time-invariant system, which gives a first insight into the reduction techniques that will be used later. Finally, a nonstationary version of the filtering problem is connected to a nonstationary Sarason problem.
KeywordsPoint Evaluation Controllability Operator Toeplitz Operator Open Unit Disc Observability Operator
Unable to display preview. Download preview PDF.