Luminosity associated to the limiting flux at each redshift. Solid curve: it represents the maximum luminosity that we are expected to see at each redshift. Yellow filled area: volume traced by all the galaxies that have a luminosity with a given luminosity bin, enclosed between L1 and L2 (horizontal solid lines). We refer to this volume as V_int Diagonally filled area: Total volume that would be traced without any limit in the minimum luminosity that we could observe. We refer to this as V_max.