Extreme sets #
This file defines extreme sets and extreme points for sets in a real vector space.
See chapter 8 of Convexity
- add exposed sets to this file.
- define convex independence and prove lemmas related to extreme points.
A set B is extreme to a set A if B ⊆ A and all points of B only belong to open segments whose ends are in B.
A point x is an extreme point of a set A if x belongs to no open segment with ends in A, except
for the obvious
open_segment x x.