Flow in Cyclic Cosmology
  In this paper, we use a known duality between expanding and contracting
cosmologies to construct a dual of the inflationary flow hierarchy applicable
to contracting cosmologies such as Ekpyrotic and Cyclic models. We show that
the inflationary flow equations are invariant under the duality and therefore
apply equally well to inflation or to cyclic cosmology. We construct a
self-consistent small-parameter approximation dual to the slow-roll
approximation in inflation, and calculate the power spectrum of perturbations
in this limit. We also recover the matter-dominated contracting solution of
Wands, and the recently proposed Adiabatic Ekpyrosis solution.
