Cosmological dark fluid from five-dimensional vacuum
  In the framework of the induced matter theory of gravity, we derive a 5D solution of the field equations that can describe a 4D cosmological scenario where the dark fluid (dark matter plus dark energy) equation of state has a geometrical origin. There is no a natural separation of the dark sector into different components, and then the model may provide a geometrical explanation for the existence of a dark degeneracy in cosmological scenarios. 
Luz M. Reyes, Jos\'e Edgar Madriz Aguilar, L Arturo Ure\~na-L\'opez
gr-qc