  Recent galaxy formation models successfully reproduce the local luminosity
function (LF) of galaxies by invoking mechanisms to suppress star formation in
low- and high-mass galaxies. As these models are optimized to fit the LF at low
redshift, a crucial question is how well they predict the LF at earlier times.
Here we compare recently measured rest-frame V-band LFs of galaxies at
redshifts 2.0<z<3.3 to predictions of semianalytic models by De Lucia & Blaizot
and Bower et al. and hydrodynamic simulations by Dave et al.. The models
succeed for some luminosity and redshift ranges and fail for others. A notable
success is that the Bower et al. model provides a good match to the observed LF
at z~3. However, all models predict an increase with time of the rest-frame
V-band luminosity density, whereas the observations show a decrease. The models
also have difficulty matching the observed rest-frame colors of galaxies. In
all models the luminosity density of red galaxies increases sharply from z~3 to
z~2.2, whereas it is approximately constant in the observations. Conversely, in
the models the luminosity density of blue galaxies is approximately constant,
whereas it decreases in the observations. These discrepancies cannot be
entirely remedied by changing the treatment of dust and suggest that current
models do not yet provide a complete description of galaxy formation and
evolution since z~3.
