A regularity result for the singular values of a transfer matrix and a quadratically convergent algorithm for computing its L/sub infinity /-norm

The ith singular value of a transfer matrix, sigma /sub i/(H(j omega )), need not be a differential function of omega at frequencies where its multiplicity is greater than one. However, near a local maximum the largest singular value sigma /sub 1/(H(j omega )) has a Lipschitz second derivative, but need not have a third derivative. On the basis of this regularity result, the authors obtain a quadratically convergent algorithm for computing the L/sub infinity /-norm of a transfer matrix.<
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