Neural Collapse Dynamics: Depth, Activation, Regularisation, and Feature Norm Threshold

ArXi:2604.00230v1 Announce Type: new Neural collapse (NC) -- the convergence of penultimate-layer features to a simplex equiangular tight frame -- is well understood at equilibrium, but the dynamics governing its onset remain poorly characterised. We identify a simple and predictive regularity: NC occurs when the mean feature norm reaches a model-dataset-specific critical value, fn*, that is largely invariant to