Faint-end slope as a function of redshift. The parameter α was computed through a maximum-likelihood analysis with a Schechter form (black solid circles refer to the BC03 library, red open boxes refer to the CB07 one) and by fitting the ensemble (this study + previous surveys) of 1/V_max points with a Schechter parametric form (blue open triangles) and a double power-law shape (see text, green open circles). The different sets are shifted in redshift with respect to the central values in each interval (shown by the solid black circles).