Extensions and Selections in Subspaces of C(K).
Extensions of Lebesgue sets and of real-valued functions
Extensions of topological algebras.
Extremal functions of the Nevanlinna-Pick problem and Douglas algebras
The Nevanlinna-Pick problem at the zeros of a Blaschke product B having a solution of norm smaller than one is studied. All its extremal solutions are invertible in the Douglas algebra D generated by B. If B is a finite product of sparse Blaschke products (Newman Blaschke products, Frostman Blaschke products) then so are all the extremal solutions. For a Blaschke product B a formula is given for the number C(B) such that if the NP-problem has a solution of norm smaller than C(B) then all its extremal...
Extremal non-compactness of weighted composition operators on the disk algebra
Extremal units in an archimedean Riesz space
Extreme and exposed representing measures of the disk algebra
We study the extreme and exposed points of the convex set consisting of representing measures of the disk algebra, supported in the closed unit disk. A boundary point of this set is shown to be extreme (and even exposed) if its support inside the open unit disk consists of two points that do not lie on the same radius of the disk. If its support inside the unit disk consists of 3 or more points, it is very seldom an extreme point. We also give a necessary condition for extreme points to be exposed...
Extreme Boundaries and continous affine functions.
Extreme positive functionals
Extreme spectral states and multiplicative extensions in Banach algebras
Extreme Spectral States of Commutative Banach Algebras.