Power-law dependence between core size (r_2% 3D Lagrangian radius) and time left to core collapse, t_cc − t. A power-law relation (appearing linear in log-log scale) holds in the initial phases of core collapse. We show it here for models with mass-function slope α = 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6, number of stars N = 2 × 10⁵, and ℛ = 10⁻³. Due to our definition of the x axis, time increases from right to left. The solid lines are data from our simulations, and the superimposed dashed lines are a robust linear fit between the initial time and t_cc − 100t_dyn. The angular coefficient of the regression lines appears to vary systematically with the mass function. As expected, the power-law relation breaks before core collapse, when the self-similar contraction phase ends.