Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-13T06:54:02.151Z Has data issue: false hasContentIssue false

Linear Maps on Factors which Preserve the Extreme Points of the Unit Ball

Published online by Cambridge University Press:  20 November 2018

Vania Mascioni
Affiliation:
Department of Mathematics The University of Texas at Austin Austin, Texas 78712 U.S.A., e-mail: mascioni@math.utexas.edu
Lajos Molnár
Affiliation:
Institute of Mathematics Lajos Kossuth University P.O. Box 12 4010 Debrecen Hungary, e-mail: molnarl@math.klte.hu
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The aim of this paper is to characterize those linear maps from a von Neumann factor $A$ into itself which preserve the extreme points of the unit ball of $A$. For example, we show that if $A$ is infinite, then every such linear preserver can be written as a fixed unitary operator times either a unital *-homomorphism or a unital $*$-antihomomorphism.

Keywords

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1998

References

[BrSe] Brešar, M. and Šemrl, P., Linear preservers on B(X). Banach Cent. Publ. 38 (1997), 4958.Google Scholar
[Hal] Halmos, P. R., A Hilbert Space Problem Book. Van Nostrand, 1967.Google Scholar
[Her] Herstein, I. N., Jordan homomorphisms. Trans. Amer.Math. Soc. 81 (1956), 331341.Google Scholar
[KaRi1] Kadison, R. V. and Ringrose, J. R., Fundamentals of the Theory of Operator Algebras, Vol I. Academic Press, 1983.Google Scholar
[KaRi2] Kadison, R. V. and Ringrose, J. R., Fundamentals of the Theory of Operator Algebras, Vol II. Academic Press, 1986.Google Scholar
[LaMa] Labuschagne, L. E. and Mascioni, V., Linear maps between C*-algebras whose adjoint preserve extreme points of the unit ball. Adv. in Math., to appear.Google Scholar
[LiTs] Li, C. K. and Tsing, N. K., Linear preserver problems: A brief introduction and some special techniques. Linear Algebra Appl. 162–164 (1992), 217235.Google Scholar
[Mar] Marcus, M., All linear operators leaving the unitary group invariant. Duke Math. J. 26 (1959), 155163.Google Scholar
[Rai] Rais, M., The unitary group preserving maps (the infinite dimensional case). Linear and Multilinear Algebra 20 (1987), 337345.Google Scholar
[RuDy] Russo, B. and Dye, H. A., A note on unitary operators in C*-algebras. Duke Math. J. 33 (1966), 413416.Google Scholar
[Sto] Størmer, E., On the Jordan structure of C*-algebras. Trans. Amer.Math. Soc. 120 (1965), 438447.Google Scholar
[StZs] Strǎtilǎ, S. and Zsidó, L., Lectures on von Neumann Algebras. Abacus Press, 1979.Google Scholar