# Russo-Dye theorem

Let $A$ be a unital $C^{*}$-algebra. Then the unit ball of $A$ is the closed convex hull of the unitaries in $A$. Moreover, these unitary elements are extreme points of the unit ball.

Title Russo-Dye theorem RussoDyeTheorem 2013-03-22 16:01:52 2013-03-22 16:01:52 aube (13953) aube (13953) 4 aube (13953) Theorem msc 47A60