exposed points are dense in the extreme points
Definition.
Let be a closed convex set. A point is called an exposedpoint if there is an dimensional hyperplane whose intersection with is alone.
Theorem (Strasziewicz).
Let be a closed convex set. Then the set of exposed points is dense in the setof extreme points.
For example, let denote the closed ball in of radius 1 and centered at Then take to be the convex hull of and . The points and areextreme points, but they are not exposed points.