On structured tangential Nevanlinna-Pick

This paper is a continuation of the work of Bercovici-Foias-Tannenbaum (1989, 1990) on interpolation problems where the interpolating functions are bounded not in norm but in spectral radius or structured singular values. These problems arise naturally in the robust control of systems with structured uncertainty. Here we extend our structured matrix Nevanlinna-Pick interpolation theory to the (one-sided) tangential case. With these results, we have laid the groundwork for a rigorous analytic procedure for /spl mu/-synthesis.<
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