Optimal L/sub infinity / bounds for disturbance robustness

Robust disturbance rejection bounds obtained recently by Zhu et al. are tight with respect to the disturbance set that has a specified L/sub 2/ norm bound. It is shown that the bounds are also tight with respect to a weighted L/sub 2/ disturbance set that has a specified bound on its outer product by choosing a special weight matrix in the L/sub 2/ norm. The matrix can computed by numerical iteration.<
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