© 1988 by Institute of Mathematics and its Applications
Uniform Stability for Time-Varying Infinite-Dimensional Discrete Linear Systems
Department of Research and Development, National Lab. for Scientific Comp.-LNCC R. Lauro Müller 455, Rio de Janeiro, 22290, Brazil
Department of Electrical Engineering, Catholic University-PUC/RJ R. Marques de S. Vicente 209, Rio de Janeiro, 22453, Brazil
Stability for time-varying discrete linear systems in a Banach space is investigated. On the one hand is established a fairly complete collection of necessary and sufficient conditions for uniform asymptotic equistability for input-free systems. This includes uniform and strong power equistability, and uniform and strong lp-equistability, among other technical conditions which also play an essential role in stability theory. On the other hand, it is shown that uniform asymptotic equistability for input-free systems is equivalent to each of the following concepts of uniform stability for forced systems: lp-input lp-state, eo-input eo-state, bounded-input bounded-state, lp-input bounded-state (with p>1), eo-input bounded-state, and convergent-input bounded-state; these are also equivalent to their nonuniform counterparts. For time-varying convergent systems, the above is also equivalent to convergent-input convergent-state stability. The proofs presented here are all lementary in the sense that they are based essentially only on the BanachSteinhaus theorem.
Keywords: Discrete-time systems; linear systems; infinite-dimensional systems; stability theory; time-varying systems.