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

top
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

top

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

top
  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. 

NotesEmbed ?

top

You must be logged in to post comments.

To embed these notes on your page include the following JavaScript code on your page where you want the notes to appear.

Only the controls for the widget will be shown in your chosen language. Notes will be shown in their authored language.

Tells the widget how many notes to show per page. You can cycle through additional notes using the next and previous controls.

    
                

Note: Best practice suggests putting the JavaScript code just before the closing </body> tag.