Face numbers of centrally symmetric polytopes from split graphs
  We analyze a remarkable class of centrally symmetric polytopes, the Hansen polytopes of split graphs. We confirm Kalai's 3^d-conjecture for such polytopes (they all have at least 3^d nonempty faces) and show that the Hanner polytopes among them (which have exactly 3^d nonempty faces) correspond to threshold graphs. Our study produces a new family of Hansen polytopes that have only 3^d+16 nonempty faces. 
Ragnar Freij, Matthias Henze, Moritz W. Schmitt, G\"unter M. Ziegler
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