Abstract
The celebrated Krein-Milman theorem guarantees that a compact convex set in a topological linear space has so many extreme points as their closed convex hull coincides with the set itself. It is, however, usually difficult to determine and parametrize all extreme points. In this paper we will determine extreme points of a positive operator ball X ≥ 0; X 2 ≤ A 2 with A ≥ 0 in the space of bounded selfadjoint operators on a Hilbert space.
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Ando, T. (2000). Extreme Points of a Positive Operator Ball. In: Adamyan, V.M., et al. Operator Theory and Related Topics. Operator Theory: Advances and Applications, vol 118. Birkhäuser, Basel. https://doi.org/10.1007/978-3-0348-8413-6_4
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DOI: https://doi.org/10.1007/978-3-0348-8413-6_4
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