FL^(s), FM^(s), and logarithmic FL^(s) × N_s versus the variability indices for stars selected by f_fluc expression, using α = 0.30 for s = 2 and α = 0.46 for s = 3 (see Sect. 6.2) for s = 2 (left panels) and s = 3 (right panels). The WVSC1 stars are indicates with open black circles and the colours are set with the K magnitude. Objects shown with crosses do not have a K-band magnitude because they are either too faint or saturated. These objects have measurements in other bands.