On exposed points and extremal points of convex sets in Rnand Hilbert space

Abstract

Let $\mathbb V$ be a Euclidean space or the Hilbert space $\ell^2$, let $ k \in \mathbb N$ with $k < \dim \mathbb V$, and let $B$ be convex and closed in $\mathbb V$. Let $\mathcal{P}$ be a collection of linear $k$-subspaces of $\mathbb V$. A set