  We compute the evolution of spatially flat, mixed cold and hot dark matter
(``MDM") models containing both baryonic matter and two kinds of dark matter.
The mean final Zeldovich-Sunyaev $y$ parameter is estimated to be $\bar
y=(5.4\pm 2.7)\times 10^{-7}$, with a rms fluctuation of approximately
$\bar{\delta y}=(6.0\pm 3.0)\times 10^{-7}$ on arc minute scales. The rate of
galaxy formation peaks at an even later epoch ($z\sim 0.3$) than in the
standard ($\Omega=1$, $\sigma_8=0.67$) CDM model ($z\sim 0.5$) and, at a
redshift of z=4 is nearly a factor of a hundred lower than for the CDM model
with the same value of $\sigma_8$. The model yields a cluster mass function
which is about a factor of 4 higher than observed but a cluster-cluster
correlation length lower by a factor of 2 than what is observed but both are
closer to observations than in the COBE normalized CDM model. The one
dimensional pairwise velocity dispersion is $605\pm 8$km/s at $1h^{-1}$
separation, lower than that of the CDM model normalized to COBE, but still
significantly higher than observations (Davis \& Peebles 1983). A plausible
velocity bias $b_v=0.8\pm 0.1$ on this scale will reduce but not remove the
discrepancy. Overall, the model is similar both on large and intermediate
scales to the standard CDM model normalized to the same value of $\sigma_8$,
but the problem with regard to late formation of galaxies is more severe in
this model than in that CDM model. Adding hot dark matter significantly
improves the ability of COBE normalized CDM scenario to fit existing
observations, but the model is in fact not as good as the CDM model with the
same $\sigma_8$ and is still probably unsatisfactory with regard to several
critical tests.
