Extreme points of the closed unit ball in C*-algebras

Rainer Berntzen

Colloquium Mathematicae (1997)

  • Volume: 74, Issue: 1, page 99-100
  • ISSN: 0010-1354

Abstract

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In this short note we give a short and elementary proof of a characterization of those extreme points of the closed unit ball in C*-algebras which are unitary. The result was originally proved by G. K. Pedersen using some methods from the theory of approximation by invertible elements.

How to cite

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Berntzen, Rainer. "Extreme points of the closed unit ball in C*-algebras." Colloquium Mathematicae 74.1 (1997): 99-100. <http://eudml.org/doc/210505>.

@article{Berntzen1997,
abstract = {In this short note we give a short and elementary proof of a characterization of those extreme points of the closed unit ball in C*-algebras which are unitary. The result was originally proved by G. K. Pedersen using some methods from the theory of approximation by invertible elements.},
author = {Berntzen, Rainer},
journal = {Colloquium Mathematicae},
keywords = {extreme points of the closed unit ball; -algebras; approximation by invertible elements},
language = {eng},
number = {1},
pages = {99-100},
title = {Extreme points of the closed unit ball in C*-algebras},
url = {http://eudml.org/doc/210505},
volume = {74},
year = {1997},
}

TY - JOUR
AU - Berntzen, Rainer
TI - Extreme points of the closed unit ball in C*-algebras
JO - Colloquium Mathematicae
PY - 1997
VL - 74
IS - 1
SP - 99
EP - 100
AB - In this short note we give a short and elementary proof of a characterization of those extreme points of the closed unit ball in C*-algebras which are unitary. The result was originally proved by G. K. Pedersen using some methods from the theory of approximation by invertible elements.
LA - eng
KW - extreme points of the closed unit ball; -algebras; approximation by invertible elements
UR - http://eudml.org/doc/210505
ER -

References

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  1. [Kad] R. V. Kadison, Isometries of operator algebras, Ann. of Math. 54 (1951), 325-338. Zbl0045.06201
  2. [Pe1] G. K. Pedersen, C*-Algebras and Their Automorphism Groups, London Math. Soc. Monographs 13, Academic Press, London, 1979. 
  3. [Pe2] G. K. Pedersen, The λ-function in operator algebras, J. Operator Theory 26 (1991), 345-382. 

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