arXiv Machine Learning

Non-Uniform Noise-to-Signal Ratio in the REINFORCE Policy-Gradient Estimator

arXiv:2602. 01460v3 Announce Type: replace-cross Abstract: Policy-gradient methods are widely used in reinforcement learning, yet training often becomes unstable or slows down as learning progresses.

arXiv AI
Jun 6

Retry Policy Gradients in Continuous Action Spaces

arXiv:2606. 05888v1 Announce Type: new Abstract: Retry-based objectives such as pass@K and max@K optimize the best return obtained from multiple sampled trajectories, and recent work has shown that they can promote exploration without explicit exploration bonuses.

By Soichiro Nishimori, Paavo Parmas
arXiv Machine Learning
2d ago

Dissimilarity-Based Markov Decision Processes for Stabilizing State Distributions

The paper introduces Dissimilarity-based Markov Decision Processes (DMDPs) to learn policies that stabilize state distributions in stochastic systems. It provides a theoretical framework, finite-dimensional distribution representation, and stability certificates that account for learning and estimation errors. Practical algorithms combine distribution estimates with PPO and SAC, demonstrated on a linear system and a HalfCheetah task to regulate velocity distributions.

By Xun Shen, Yuepeng Wang, Daniyal Sajedi-Hosseini, Akifumi Wachi, Ken Kawano, Yoshihiko Fujisawa, Mehrshad Sadria, S\'ebastien Gros, Katsuki Fujisawa
arXiv Machine Learning
Sep 24

Limiting-Kernel Q($\lambda$): Bridging Short and Long Horizons

Limiting‑Kernel Q(λ) (LKQL) is an off‑policy value estimator that blends n‑step truncation with a long‑horizon approximation based on the limiting kernel. It maintains the computational efficiency of n‑step methods while improving policy evaluation accuracy, especially for long‑horizon tasks. The authors prove faster convergence of LKQL’s operator under aperiodicity and near‑on‑policy conditions, and demonstrate empirical gains on MuJoCo continuous‑control benchmarks.

By Tolga Ok, Arman Sharifi Kolarijani, Peyman Mohajerin Esfahani, Mohamad Amin Sharifi Kolarijani
arXiv Machine Learning
Jun 11

Mirror Descent Beyond Euclidean Stability: An Exponential Separation in Initialization Sensitivity

arXiv:2606. 11431v1 Announce Type: new Abstract: Mirror Descent (MD) extends Gradient Descent (GD) beyond Euclidean geometry and has recently reappeared as a lens for KL-regularized policy optimization in reinforcement learning and LLM post-training.

By Shira Vansover-Hager, Matan Schliserman, Ofir Schlisselberg, Tomer Koren