Model Independent Tests of Cosmic Gravity
  Gravitation governs the expansion and fate of the universe, and the growth of
large scale structure within it, but has not been tested in detail on these
cosmic scales. The observed acceleration of the expansion may provide signs of
gravitational laws beyond general relativity. Since the form of any such
extension is not clear, from either theory or data, we adopt a model
independent approach to parametrising deviations to the Einstein framework. We
explore the phase space dynamics of two key post-GR functions and derive a
classification scheme and an absolute criterion on accuracy necessary for
distinguishing classes of gravity models. Future surveys will be able to
constrain the post-GR functions' amplitudes and forms to the required
precision, and hence reveal new aspects of gravitation.
