Universality for quintessence
  Several recent works suggested the possibility of describing inflation by
means of a renormalization group equation. In this paper we discuss the
application of these methods to models of quintessence. In this framework a
period of exponential expansion corresponds to the slow evolution of the scalar
field in the neighborhood of a fixed point. A minimal set of universality
classes for models of quintessence is defined and the transition from a matter
dominated to quintessence dominated universe is studied. Models in which
quintessence is non-minimally coupled with gravity are also discussed. We show
that the formalism proves to be extremely convenient to describe quintessence
and moreover we find that in most of the models discussed in this work
quintessence naturally takes over ordinary matter.
