Stellar mass function of galaxies at z = 0. The filled squares show the galaxy mass function determined observationally by Bell et al. (2003). The solid line shows our best-fit model (the “full” model, with parameter values listed in Table 1). The fit assumes h = 0.7 because observationally inferred masses scale as h^-2. a) Variations of the stellar mass function for different assumptions on merging and stripping: best-fit full model (black solid line), no tidal stripping (η_strip = 0, red dotted line), no mergers at all (green dashed line), and maximum merging (blue dash-dotted line); b) variations of the stellar mass function for different assumptions on the baryonic physics: best-fit full model (black solid line, same as in panel a), baryons trace dark matter (m_stars = f_b   M_halo, red dotted line), no high-mass cutoff (M_shock → ∞, green dashed line), and no low circular velocity cutoff (v_SN = v_reion = 0, blue dash-dotted line). In both panels, all variations start from the best-fit parameters of the full model except for the fact that we use η_strip = 0 in all models apart from the full one.