×

The faces of the unit balls of \(c\)-norms and \(c\)-spectral norms. (English) Zbl 0923.15014

Summary: We give a complete description of the faces of the closed unit ball of an arbitrary \(c\)-norm on \(\mathbb{R}^n\), and we determine the barycenter, the volume, and the symmetries of each face. As a consequence of a previous result we characterize the faces of the closed unit ball of the corresponding \(c\)-spectral norm on the space of \(n\times m\) real (or complex) matrices.

MSC:

15A60 Norms of matrices, numerical range, applications of functional analysis to matrix theory
Full Text: DOI

References:

[1] Berger, M., Géométrie, Cédic (1979), Fernand Nathan: Fernand Nathan Paris
[2] Borsuk, K., Multidimensional Analytic Geometry (1969), Polish Scientific Publishers: Polish Scientific Publishers Warszawa · Zbl 0189.21201
[3] Chang, S.; Li, C. K., Certain isometries on \(R^n\), Linear Algebra Appl., 165, 251-265 (1992) · Zbl 0743.15013
[4] Gantmacher, F. R., The Theory of Matrices (1960), Chelsea: Chelsea New York · Zbl 0088.25103
[5] Gohberg, I.; Krein, M., Introduction to the Theory of Nonselfadjoint Operators, (Transl. Math. Monographs, 18 (1969), Amer. Math. Soc: Amer. Math. Soc Providence) · Zbl 0181.13504
[6] Householder, A., The approximate solution of matrix problems, J. Assoc. Comput. Mach., 5, 205-243 (1958) · Zbl 0094.31003
[7] Li, C. K.; Tsing, N. K., Duality between some linear preserver problems. II. Isometries with respect to \(c\)-spectral norms and matrices with fixed singular values, Linear Algebra Appl., 110, 181-212 (1988) · Zbl 0655.15026
[8] Marshall, A.; Olkin, I., Inequalities: Theory of Majorization and Its Applications (1972), Academic: Academic New York
[9] Mirsky, L., Symmetric gauge functions and unitarily invariant norms, Quart. J. Math. Oxford, 11, 50-59 (1960) · Zbl 0105.01101
[10] Rockafellar, R., Convex Analysis (1970), Princeton U.P: Princeton U.P Princeton · Zbl 0193.18401
[11] de Sá, E. M., Faces and traces of the unit ball of a symmetric gauge function, Linear Algebra Appl., 197, 198, 349-395 (1996) · Zbl 0808.15013
[12] de Sá, E. M., Faces of the unit ball of a unitarily invariant norm, Linear Algebra Appl., 197, 198, 451-493 (1994) · Zbl 0808.15014
[13] de Sá, E. M., Exposed faces and duality for symmetric and unitarily invariant norms, Linear Algebra Appl., 197, 198, 429-450 (1994) · Zbl 0808.15015
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.