The Cauchy problem for f(R)-gravity: an overview
  We review the Cauchy problem for f(R) theories of gravity, in metric and
metric-affine for- mulations, pointing out analogies and differences with
respect to General Relativity. The role of conformal transformations, effective
scalar fields and sources in the field equations is discussed in view of the
well-posedness of the problem. Finally, criteria of viability of the
f(R)-models are considered according to the various matter fields acting as
sources.
