Global density D8 vs. distance from the nearest filament axis D_fil for groups (left panel) and for single galaxies (right panel). The colours denote groups in four luminosity classes. The horizontal lines indicate global luminosity–density limits D8 = 1.15, D8 = 2.38, D8 = 5.0, and D8 = 7.0. The vertical lines show the characteristic distances from the nearest filament axis, D_fil = 0.5 Mpc and D_fil = 2.5 Mpc.