V. Ionescu et C. Oara, DISCRETE-TIME EXTENDED NEHARI PROBLEM - THE GENERAL-CASE, Zeitschrift fur angewandte Mathematik und Mechanik, 76, 1996, pp. 463-464
Using the generalized Popov theory, an explicit solution to the discre
te Nehari problem (the 4 block case) together with a complete characte
rization of the class of all solutions are given. The derivation is ma
de under no restrictive (time-reversibility) conditions imposed on the
system to be approximated. This approach is an alternative to the sol
ution proposed, for the continuous-time case, in [1] and [2]. An exten
ded version of this paper is in preparation [3].