  The cluster and field luminosity functions (LFs) determined on large
homogeneous samples (N>2200 galaxies each) are almost indistinguishable, down
to M^*+4 in the r and i filters, hence suggesting that the effect of the
cluster environment on the galaxy properties does not affect the galaxy
luminosity function in red bands. The similarity of the red band LFs in
different environments suggests that the galaxy mass function is preserved
during the galaxy infall in the cluster. By analyzing a large sample of
galaxies in clusters, ideal from many points of view (multicolor data, large
size, many clusters, metric magnitudes) we found that luminosity evolution is
required by the data but the latter do not unambiguously derive its flavour if
a differential luminosity evolution between bright and faint galaxies is
allowed. We show that the LF parameters (slope, characteristic magnitude and
their evolution) and errors depend on assumptions in a way seldom recognized in
literature. We also point out logical inconsistencies between hypothesis
assumed in deriving literature LF and presented results, suggesting caution in
interpreting similar published results.
