arXiv Machine Learning

Learning Metastable Dynamics

arXiv AI
Aug 25

FreKoo++: Learning Continuous Spectral Dynamics for Temporal Domain Generalization

FreKoo++ is a continuous spectral-dynamical framework designed for Temporal Domain Generalization (TDG). It unifies continuous Koopman modal dynamics with adaptive spectral disentanglement, mapping source-domain parameters into a latent space and modeling their evolution as a superposition of learnable continuous modes. The method handles irregular timestamps, supports arbitrary horizon extrapolation, and introduces an adaptive soft spectral weighting mechanism that isolates persistent dynamics from transient noise, achieving state‑of‑the‑art performance on discrete and continuous TDG benchmarks.

By En Yu, Xiaoyu Yang, Wei Duan, Guangquan Zhang, Jie Lu
arXiv Machine Learning
Aug 31

Shift Before You Learn: Enabling Low-Rank Representations in Reinforcement Learning

The paper challenges the common assumption that the successor measure in reinforcement learning is approximately low-rank, showing instead that a low-rank structure emerges in a shifted successor measure that ignores initial transitions. It provides finite-sample guarantees for estimating this low-rank approximation, introduces Type II Poincaré inequalities to bound spectral recoverability, and links the necessary shift to the decay of high-order singular values and local mixing properties. Experiments confirm that shifting the successor measure improves goal-conditioned RL performance.

By Bastien Dubail, Stefan Stojanovic, Alexandre Prouti\`ere
arXiv Machine Learning
Sep 22

In-context learning from self-generated trajectories for adaptive model reduction

The paper introduces an in‑span adaptation technique for reduced‑order models, where the reduced subspace is continually updated using the model’s own predictions via an incremental singular‑value decomposition with a forgetting factor. This creates a trajectory‑informed spectral preconditioner that reweights and realigns the basis without changing the subspace, enabling the model to better absorb future out‑of‑span corrections. The authors demonstrate the method on a 3‑D spiral example and nonlinear PDEs such as viscous Burgers and Fisher–KPP, and relate the approach to in‑context learning in dynamical systems.

By Amirpasha Hedayat, Laura Balzano, Karthik Duraisamy
arXiv AI
Sep 18

Regularized Emphatic Temporal-Difference Learning: Stability under Constant Stepsizes

The paper introduces Regularized Emphatic Temporal‑Difference Learning (RETD), a modification of ETD that normalizes the post‑shock dynamics while preserving the emphatic TD signal and importance ratios. RETD achieves almost‑sure convergence under harmonic diminishing stepsizes and provides a conditional constant‑stepsize moment‑contraction guarantee, demonstrating negative Lyapunov exponents on a two‑state counterexample and the Baird point. Extensive experiments confirm RETD’s ability to recover the ETD fixed point, exhibit a non‑monotone stability region, and maintain task‑dependent performance.

By Xingguo Chen, Zhaohui Wu, Jinguo Ye, Chao Li, Shangdong Yang, Guang Yang, Skylar Liang, Wenhao Wang