  We calculate the statistical clustering of Lyman-break galaxies predicted in
a selection of currently-fashionable structure formation scenarios. These
models are all based on the cold dark matter model, but vary in the amount of
dark matter, the initial perturbation spectrum, the background cosmology and in
the presence or absence of a cosmological constant term. If Lyman-break
galaxies form as a result of hierarchical merging, the amplitude of clustering
depends quite sensitively on the minimum halo mass that can host such a galaxy.
Interpretation of the recent observations by Giavalisco et al. (1998) would
therefore be considerably clarified by a direct determination of the relevant
halo properties. For a typical halo mass around $10^{11} h^{-1} M_\odot$ the
observations do not discriminate strongly between cosmological models, but if
the appropriate mass is larger, say $10^{12} ~h^{-1} M_\odot$ (which seems
likely on theoretical grounds), then the data strongly favour models with a low
matter-density.
