  We revisit the dynamics of the one-dimensional self-gravitating sheets
models. We show that homogeneous and non-homogeneous states have different
ergodic properties. The former is non-ergodic and the one-particle distribution
function has a zero collision term if a proper limit is taken for the periodic
boundary conditions. Non-homogeneous states are ergodic in a time window of the
order of the relaxation time to equilibrium, as similarly observe in other
systems with a long range interaction. For the sheets model this relaxation
time is much larger than other systems with long range interactions if compared
to the initial violent relaxation time.
