Extensions des -algèbres
Extensions of certain real rank zero -algebras
G. Elliott extended the classification theory of -algebras to certain real rank zero inductive limits of subhomogeneous -algebras with one dimensional spectrum. We show that this class of -algebras is not closed under extensions. The relevant obstruction is related to the torsion subgroup of the -group. Perturbation and lifting results are provided for certain subhomogeneous -algebras.
Extensions of derivations II.
Extensions of dimension groups and AF C*-algebras.
Extensions of stable -algebras.
Extremal problems for completely positive maps.
Extreme points of the closed unit ball in C*-algebras
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.
Extreme Positive Linear Maps on C*-Algebras.