  We compare the conclusions reached using the coarse-graining technique
employed by Henriksen (2004) for a one degree of freedom (per particle)
collisionless system, to those presented in a paper by Binney (2004) based on
an exact one degree of freedom model. We find agreement in detail but in
addition we show that the isolated 1D system is self-similar and therefore
unrelaxed. Fine graining of this system recovers much less prominent wave-like
structure than in a spherically symmetric isotropic 3D system. The rate of
central flattening is also reduced in the 1D system. We take this to be
evidence that relaxation of collisionless systems proceeds ultimately by way of
short wavelength Landau damping. N-body systems, both real and simulated, can
be trapped in an incompletely relaxed state because of a break in the cascade
of energy to small scales. This may be due to the rapid dissipation of the
small scale oscillations in an isolated system, to the existence of conserved
quantities such as angular momentum, or to the failure in simulations to
resolve sub-Jeans length scales. Such a partially relaxed state appears to be
the NFW state, and is to be expected especially in young systems. The NFW core
is shown to be isolated. In non-isolated systems continuing coarse-grained
relaxation should be towards a density core in solid body rotation.
