The Hansen polytope 
of a graph 
on 
vertices is the twisted prism of its stable set polytope 
, the convex
hull of the characteristic vectors of
the independent vertex sets of 
. Explicitly,
 |
It is a centrally symmetric convex polytope of dimension 
.
Empty graphs produce hypercubes,
while complete graphs produce cross
polytopes. The Hansen polytopes of split graphs
satisfy Kalai's 3d conjecture
(Freij et al. 2013).
