Convex Polytope Face
# Definition 1
Let $V$ be an Inner Product Space over $\mathbb{R}$ and let $P \subset V$ be a Convex Polytope. Then a Set $F \subset P$ is a face of $P$ if any of the following is true:
- $F = P$
- $F = \emptyset$
- there exists a Supporting Hyperplane $H \subset V$ so that $F = P \cap H$.
# Properties
# Definition 2
TODO - definition in terms of Valid Inequalitys.