Evolution of the fraction of “dwarf” galaxies (stellar mass <5 ×10⁸ h⁻¹ M_⊙) identified in the De Lucia & Blaizot (2007) semianalytical model of galaxy formation run on the Millennium Simulation. These systems are excluded from further analysis for the reasons discussed in Section 2.4.6. The exclusion of dwarf galaxies results in a lower limit on the number of identified CGs that becomes increasingly more significant at higher redshift. For z < 0.5, the fraction of excluded galaxies based on the mass criterion is ≲60%. The fraction rises rapidly for z > 1. See Section 2.4.6 for further discussion.