Absence of critical scaling in the Schelling segregation model

arXiv:2608.16557 2026 Dynamics 1 ideas extracted · analyzed Sep 1, 2026

What the math gives to ML

The paper identifies a quantitative mechanism in which transitions are caused by finite, subcritical relocation cascades rather than critical long-range correlations. A branching ratio R below one predicts a finite mean cascade size of 1/(1-R), while susceptibility grows sharply as R approaches one. This can transfer to neural networks as a cascade-stability controller: perturb activations, gradients, or parameter blocks, estimate how many new computational events are triggered, and regulate learning rate or residual gain before the effective branching ratio reaches one.

Ideas from this paper

Unverified 2026

Subcritical Gradient-Cascade Control

Treat a small activation, gradient, or parameter perturbation as a seed and measure the number of newly affected downstream units or layers. Use the estimated branching ratio to control the optimizer step size or residual gains, keeping training in a subcritical regime where perturbation cascades have finite expected size instead of amplifying through the whole network.

Useful6/10
Difficulty5/10
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Paper: Absence of critical scaling in the Schelling segregation model arXiv:2608.16557