  We study the effect of primordial non-Gaussianity on the development of
large-scale cosmic structure using high-resolution N-body simulations. In
particular, we focus on the topological properties of the "cosmic web",
quantitatively characterized by the Minkowski Functionals, for models with
quadratic non-linearities with different values of the usual non-Gaussianity
parameter fNL. In the weakly non-linear regime, we find that analytic formulae
derived from perturbation theory agree with the numerical results within a few
percent of the amplitude of each MF when |fNL|<1000. In the non-linear regime,
the detailed behavior of the MFs as functions of threshold density deviates
more strongly from the analytical curves, while the overall amplitude of the
primordial non-Gaussian effect remains comparable to the perturbative
prediction. When smaller-scale information is included, the influence of
primordial non-Gaussianity becomes increasingly significant statistically due
to decreasing sample variance. We find that the effect of the primordial
non-Gaussianity with |fNL|=50 is comparable to the sample variance of mass
density fields with a volume of 0.125(Gpc/h)^3 when they are smoothed by
Gaussian filter at a scale of 5Mpc/h. The detectability of this effect in
actual galaxy surveys will strongly depend upon residual uncertainties in
cosmological parameters and galaxy biasing.
