Training methods
arxiv arXiv cs.LG · 8d ago

Learning Fair Pareto-Optimal Policies in Multi-Objective Reinforcement Learning

The paper introduces a framework for multi-policy multi-objective reinforcement learning that learns a set of Pareto-optimal policies ensuring fairness across diverse user preferences. It proves fair policies remain within the convex coverage set for concave welfare functions and proposes three algorithms that incorporate non-stationary and stochastic policy dynamics. Empirical results show these methods effectively learn fair policies adaptable to varying user preferences.

arxiv arXiv cs.LG · 8d ago

MGUP: Momentum-Gradient Alignment for Selective Optimization

MGUP introduces a selective update mechanism that applies larger step-sizes to a fixed proportion of parameters in stochastic optimization, while using smaller, non-zero step-sizes for the rest. It integrates seamlessly with optimizers like AdamW, Lion, and Muon, providing theoretical convergence guarantees for MGUP-AdamW and demonstrating superior or more stable performance in training large language models and MAE pretraining tasks.

arxiv arXiv cs.LG · 8d ago

Reversal Q-Learning: A New Off-Policy RL Algorithm

Reversal Q-Learning (RQL) is a new off-policy reinforcement learning algorithm that trains a flow policy using prior data. By modeling flow refinement steps as actions in an expanded Markov decision process and applying virtual on-policy trajectories via reversal, RQL enables effective offline learning without backpropagation through time. Experiments on 50 robotic tasks show RQL achieves the best average performance among state-of-the-art flow-based offline RL methods.

arxiv arXiv cs.LG · 8d ago

Credit-in-Event: Re-Anchoring Event Credit in Dynamics Models

A new method called Credit-in-Event identifies and addresses temporal credit dilution in learned dynamics models. CREST, a label-free and training-free readout, re-anchors pooled representations by estimating transient event cores and applying event-versus-rest contrast, reducing out-of-distribution error across multiple systems and data types. Ablations confirm the improvement stems from event-core credit re-anchoring, not generic locality or stability priors.