Lipschitz Disagreement Coverage
Implementation & benchmark of arXiv:2608.17956 — An Omitted Mode Is a Rare Rule: The Sampling-Verification Danger Law in Continuous Code World Models
Source paper: An Omitted Mode Is a Rare Rule: The Sampling-Verification Danger Law in Continuous Code World Models arXiv:2608.17956 ⓘ · analyzed Sep 1, 2026
AI-generated research hypothesis, automatically tested. Not peer-reviewed.
Idea description
Use the localization theorem to turn a detected pointwise simulator error into a guaranteed region that must contain similarly large error, then place verification samples inside that region instead of sampling uniformly. The same bound can guide a training regularizer: errors with large amplitude and large local Lipschitz constants are penalized because they create planner-exploitable disagreement regions.
Formulas
Mathematical statement
Let z=(s,a) lie in a domain D of dimension q=d+m, where d is the state dimension and m is the action dimension. Let f and g be the reference and learned transition maps, each L-Lipschitz in the same metric: ||f(z)-f(z')|| <= L d(z,z') and ||g(z)-g(z')|| <= L d(z,z'). If ||f(z_0)-g(z_0)||=eta at z_0 and eta>epsilon, then ||f(z)-g(z)|| >= eta-2L d(z,z_0). Therefore every point with d(z,z_0)<(eta-epsilon)/(2L) has disagreement greater than epsilon. The disagreement set contains the domain-intersected metric ball with volume at least kappa*((eta-epsilon)/L)^q, where kappa=1 at an interior point and the sharp box-corner value is kappa=2^{-q}. Here eta is pointwise error amplitude, epsilon is verification tolerance, L is a common Lipschitz bound, q is domain dimension, kappa is the boundary-volume constant, and z_0 is the offending state-action input. If p is the gate probability mass of this region, N tests miss it with probability (1-p)^N.
Implementation notes
Integrate this into learned transition-model verification, with an optional training regularizer. For each candidate model, maintain a reference transition function f, learned transition g, and a probe set of state-action points z=(s,a). At every probe compute e(z)=||f(z)-g(z)||. When e(z0)=eta exceeds epsilon, estimate local Lipschitz constants for both models using spectral-norm products of MLP layers or empirical slopes L_hat=max_j ||h(z_j)-h(z0)||/d(z_j,z0), then set L=max(L_f,L_g). Construct rho=(eta-epsilon)/(2L). Generate additional verification points inside D intersected with the metric ball B(z0,rho), clipping points to the legal state-action box and using kappa=2^{-(d+m)} at a corner. Pseudocode: find z0=max-error probe; compute eta and L; if eta>epsilon, rho=(eta-epsilon)/(2L); sample K directions u_k uniformly on the unit sphere; set z_k=clip(z0+rho*u_k,D); compare f(z_k) and g(z_k); update the gate distribution toward regions with high disagreement. For training, add lambda*max(0,e(z)-epsilon)^2 or penalize L_hat when eta is large. The theorem determines rho and the volume guarantee; actual gate mass p and local L estimates are empirical. Begin with a two-dimensional cart or pendulum simulator and an MLP transition model, comparing uniform verification against adaptive ball sampling at equal model evaluations. Success is higher detection probability and lower planner regret at fixed N, especially for boundary-localized errors.
Verification
This idea has not been verified yet.
Verification happens in two stages: Stage 1 — a mechanism check on a toy system confirms the claimed mathematical phenomenon reproduces; Stage 2 — a benchmark implements the idea on a real (small) neural network task and compares it against a tuned baseline over 8 paired seeds with a permutation test.
Artifacts
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