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Linear Maps on Hermitian Matrices: The Stabilizer of an Inertia Class

Published online by Cambridge University Press:  20 November 2018

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Abstract

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Let T be a linear transformation acting on the space of n x n complex matrices. Let G(k) be the set of all hermitian matrices with k positive and n — k negative eigenvalues. Let T map some indefinite inertia class G(k) onto itself. We classify all such T. The possibilities are congruence, congruence followed by transposition, and, if n = 2k, it is possible that — T can be a congruence or a congruence followed by transposing. In other words, negation is an admissible transformation when n = 2k.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1985

References

1. Choi, M.D., Positive linear maps, Proc. Symp. in Pure Math., 38(II) (1982), pp. 583590.Google Scholar
2. Helton, J.W. and Rodman, L., Signature preserving linear maps on hermitian matrices, submitted.Google Scholar
3. Marshall, A. and Olkin, I., Inequalities: The Theory of Majorization and its Applications, Academic Press, 1979.Google Scholar
4. Schneider, H., Positive operators and an inertia theorem, Numer. Math., 7 (1965), pp. 1117.Google Scholar