  Data on galaxies at high redshift, identified by the Lyman-break photometric
technique, can teach us about how galaxies form and evolve. The stellar masses
and other properties of such Lyman break galaxies (LBGs) depend sensitively on
the details of star formation. In this paper we consider three different star
formation prescriptions, and use semi-analytic methods applied to the
now-standard $\Lambda$CDM theory of hierarchical structure formation to show
how these assumptions about star formation affect the predicted masses of the
stars in these galaxies and the masses of the dark matter halos that host them.
We find that, within the rather large uncertainties, recent estimates of the
stellar masses of LBGs from multi-color photometry are consistent with the
predictions of all three models. However, the estimated stellar masses are more
consistent with the predictions of two of the models in which star formation is
accelerated at high redshifts $z\gsim3$, and of these models the one in which
many of the LBGs are merger-driven starbursts is also more consistent with
indications that many high redshift galaxies are gas rich. The clustering
properties of LBGs have put some constraints on the masses of their host halos,
but due to similarities in the halo occupation of the three models we consider
and degeneracies between model parameters, current constraints are not yet
sufficient to distinguish between realistic models.
