Dependence of the four defined Fisher discriminants on z_spec and . For each Fisher discriminant, we present the VIPERS data (main patch), while the VVDS/F22 data are displayed at log₁₀( in z_spec bin only to illustrate the redshift dependence over 0 <z_spec< 1.2. The horizontal dashed line represents the approximate of objects with S/N = 3. We recall that we only consider galaxies detected in the SDSS. We only display bins with at least ten galaxies.