Dark energy and dark matter from nonlocal ghost-free gravity theory
  We suggest a class of generally covariant ghost-free nonlocal gravity models
generating de Sitter or Anti-de Sitter background with an arbitrary value of
the effective cosmological constant and featuring a mechanism of dark matter
simulation. These models interpolate between the general relativistic phase on
a flat spacetime background and their strongly coupled infrared (Anti)-de
Sitter phase with two propagating massless graviton modes.
