The structure of Deitmar Schemes, II. Zeta functions and automorphism   groups
  We provide a coherent overview of a number of recent results obtained by the authors in the theory of schemes defined over the field with one element. Essentially, this theory encompasses the study of a functor which maps certain geometries including graphs to Deitmar schemes with additional structure, as such introducing a new zeta function for graphs. The functor is then used to determine automorphism groups of the Deitmar schemes and base extensions to fields. 
Manuel Merida-Angulo, Koen Thas
math.AG