Upper panels: central sections of the high-resolution non-smoothed density fields of identical 256 × 256 × 1 h⁻¹ Mpc slices of DM models L512.00 and L512.10, found for particle-density limits δ₀ = 0,  10. Lower panel: slice through the zoomed density field of the SDSS.21 galaxy sample, smoothed with 1 h⁻¹ Mpc kernel. The size of the sample in the vertical direction is about 240 h⁻¹ Mpc. This figure illustrates the effect of zero-density regions in simulated and real density fields of galaxies. Densities are expressed in logarithmic scale in the interval 0.005–15 in mean density units. The colour code is identical in all panels.