Infinite-Horizon Inverse Linear-Quadratic Differential Games with State- and Control-Dependent Noise

arXiv:2608.17939 2026 Theory 1 ideas extracted · analyzed Sep 1, 2026

What the math gives to ML

The paper provides a constructive inverse mechanism for stochastic linear-quadratic Nash equilibria: once equilibrium feedback gains are observed, the compatible state and control cost parameters lie in an explicitly computable kernel intersected with admissibility constraints. The transferable asset is an identifiability certificate: equilibrium behavior generally determines a family of objectives rather than a unique objective, and the dimension of that family can be measured by a nullspace calculation. In neural networks, this can be adapted to infer or constrain local quadratic loss metrics and optimizer preconditioners from observed parameter-update trajectories, while explicitly exposing which curvature directions are unidentifiable.

Ideas from this paper

Unverified 2026

Nullspace Inverse-Loss Identification

Use a window of observed neural-network update trajectories to identify the set of local quadratic objectives and preconditioners that are consistent with the observed optimizer behavior. Rather than selecting one arbitrary curvature model, retain the nullspace of compatible parameters and use its dimension or smallest singular value as an identifiability and stability diagnostic.

Useful6/10
Difficulty6/10
Novelty8/10
Paper: Infinite-Horizon Inverse Linear-Quadratic Differential Games with State- and Control-Dependent Noise arXiv:2608.17939