Distributions comparison. Distribution in terms of ϱ_true of the high-density and low-density samples, identified using ϱ_rec in four representative redshift bins (labelled on top of each plot). In particular, the black histogram is the ϱ_true distribution shown as a reference, the cyan histogram refers to D₇₅ϱ_rec, while the red histogram refers to D₂₅ϱ_rec. The environmental estimate has been performed with n = 1.5, R = 1 Mpc and σ_{Δz/ (1 + z)} = 0.01. The two vertical dashed lines are the values of environmental density corresponding to the 25th and 75th percentile of the ϱ_true distribution.