How Fabulous Is Fab 5 Cosmology?
  Extended gravity origins for cosmic acceleration can solve some fine tuning
issues and have useful characteristics, but generally have little to say
regarding the cosmological constant problem. Fab 5 gravity can be ghost free
and stable, have attractor solutions in the past and future, and possess self
tuning that solves the original cosmological constant problem. Here we show
however it does not possess all these qualities at the same time. We also
demonstrate that the self tuning is so powerful that it not only cancels the
cosmological constant but also all other energy density, and we derive the
scalings of its approach to a renormalized de Sitter cosmology. While this
strong cancellation is bad for the late universe, it greatly eases early
universe inflation.
