Top: Normalisation, N_g0, for the mass-richness relation as a function of redshift. The lines show the third-order polynomial approximation. The normalisation is given for log₁₀M = 14, with M in units of solar mass. Bottom: Slope parameter, α, of the mass-richness relation as a function of redshift. The dotted lines show fits of linear relations. The colours have the same meaning as above.