  The processes governing both the formation and evolution of elliptical
galaxies are discussed by means of a new multi-zone photo-chemical evolution
model for elliptical galaxies, taking into account detailed nucleosynthetic
yields, feedback from supernovae, Pop III stars and an initial infall episode.
  By comparing model predictions with observations, we derive a picture of
galaxy formation in which the higher is the mass of the galaxy, the shorter are
the infall and the star formation timescales. In particular, by means of our
model, we are able to reproduce the overabundance of Mg relative to Fe,
observed in the nuclei of bright ellipticals, and its increase with galactic
mass.
  This is a clear sign of an anti-hierarchical formation process. Therefore, in
this scenario, the most massive objects are older than the less massive ones,
in the sense that larger galaxies stop forming stars at earlier times.
  Each galaxy is created outside-in, i.e. the outermost regions accrete gas,
form stars and develop a galactic wind very quickly, compared to the central
core in which the star formation can last up to ~1.3 Gyr. This finding will be
discussed at the light of recent observations of the galaxy NGC 4697 which
clearly show a strong radial gradient in the mean stellar [<Mg/Fe>] ratio.
  The role of galactic winds in the IGM/ICM enrichment will also be discussed.
