Suppose E is fully symmetric Banach function space on (0,1) or (0, ∞) or a fully symmetric Banach sequence space. We give necessary and sufficient conditions on f ∈ E so that its orbit Ω (f) is the closed convex hull of its extreme points. We also give an application to symmetrically normed ideals of compact operators on a Hilbert space.
- Fully symmetric spaces
- Hardy-littlewood majorization