Realization theory of discrete-time nonlinear systems: Part I-The bounded case

A state-space realization theory is presented for a wide class of discrete time input/output behaviors. Although in many ways restricted, this class does include as particular cases those treated in the literature (linear, multilinear, internally bilinear, homogeneous), as well as certain nonanalytic nonlinearities. The theory is conceptually simple, and matrixtheoretic algorithms are straightforward. Finite-realizability of these behaviors by state-affine systems is shown to be equivalent both to the existence of high-order input/output equations and to realizability by more general types of systems.