Multiblock problems for almost periodic matrix functions of several variables
Leiba Rodman, Ilya M. Spitkovsky, Hugo J. Woerdeman · 2001
Abstract. In this paper we solve positive and contractive multiblock problems in the Wiener algebra of almost periodic functions of several variables. We thus generalize the classical four block problemthat appears in robust control in many ways. The necessary and sufficient conditions are in terms of appropriate Toeplitz (positive case) and Hankel operators (contractive case) on Besikovitch space. In addition, a model matching interpretation is given, and some more general patterns are treated as well. Contents