  We derive the luminosity and multiplicity functions of superclusters compiled
for the 2dF Galaxy Redshift Survey, the Sloan Digital Sky Survey (Data Release
4), and for three samples of simulated superclusters. We find for all
supercluster samples Density Field (DF) clusters, which represent high-density
peaks of the class of Abell clusters, and use median luminosities/masses of
richness class 1 DF-clusters to calculate relative luminosity/mass functions.
We show that the fraction of very luminous (massive) superclusters in real
samples is more than tenfolds greater than in simulated samples. Superclusters
are generated by large-scale density perturbations which evolve very slowly.
The absence of very luminous superclusters in simulations can be explained
either by non-proper treatment of large-scale perturbations, or by some yet
unknown processes in the very early Universe.
