arXiv Machine Learning

Reinforcement Learning as (Discrete) Potential Theory

The paper discusses how reinforcement learning theory relies on probability theory via Markov chains and highlights a deep link between probability theory and potential theory. It reviews this connection and examines how a potential-theoretic perspective can be applied to core RL representations and algorithms under a fixed‑policy assumption, suggesting possible gains in sample efficiency and formal constraints. The authors also note that relaxing the fixed‑policy assumption allows the linear potential theory framework to extend naturally to nonlinear cases.

arXiv AI
Aug 21

Adaptive Probabilistic Shielding by Learning MDPs for Safe Reinforcement Learning

arXiv:2608. 19836v1 Announce Type: cross Abstract: Probabilistic shielding is a technique for safe reinforcement learning (RL).

By Astrid Horn Brorholt (Aalborg University, Aalborg, Denmark), Maris F. L. Galesloot (Radboud University, Nijmegen, Netherlands), Nils Jansen (Radboud University, Nijmegen, Netherlands), Kim Guldstrand Larsen (Aalborg University, Aalborg, Denmark), Christian Schilling (Aalborg University, Aalborg, Denmark)
arXiv AI
Sep 4

The Dually Flat Geometry of Planning as Inference

The paper offers a new way to view the occupancy measure in reinforcement learning by embedding the planning criterion into the dynamics via a resetting planning process. The resulting stationary measure, called the visitation measure, forms a dually flat statistical manifold with two affine charts: visitation probabilities and log-policies, which are dual under conditional entropy. This geometric framework allows planning-as-inference to extend beyond linear rewards to nonlinear functionals of visitation, with each iteration solvable by a natural-gradient step and provides a new interpretation of the temporal-difference error as a marginal-utility estimate.

By Nikola Milosevic, Asaki Kataoka, Nicolas Hinrichs, Kenji Doya, Nico Scherf
arXiv Machine Learning
Sep 15

Learning to Solve Stochastic Controls with Unknown Drifts and Running Rewards: Theory, Algorithms and Convergence

The paper investigates continuous‑time stochastic control problems with unknown drift and running reward functions, using an exploratory reinforcement learning framework that incorporates relaxed controls and entropy regularization. It develops policy‑iteration algorithms based on probabilistic representations of the optimal value function and its gradient, proving convergence and demonstrating performance through numerical examples. The study also extends to a special case with control‑dependent diffusion, requiring a Hessian representation.

By Jin Ma, Gaozhan Wang, Jianfeng Zhang, Xunyu Zhou
arXiv Machine Learning
1d ago

Towards Optimal Policy Improvement

The paper introduces a framework for optimal policy improvement in reinforcement learning, defining it as the best single update under given constraints. It shows that restricting improvement to a subset of states is equivalent to solving an induced Markov Decision Process, linking planning with explicit or implicit models to optimal policy improvement. The authors develop a novel operator for greedification under approximate evaluation, demonstrating empirical gains across several RL algorithms and settings.

By Yaniv Oren, Viliam Vadocz, Wiktor Zabka, Thomas Evers, Jan Robine, Wendelin B\"ohmer, Matthijs T. J. Spaan, Martha White, Hendrik Baier, Fenghui Yu
arXiv AI
Aug 19

Policy-Invariant Reward Shaping from LLM Feedback: A Framework for Hybrid RL Agents

The paper introduces a framework for combining large language models (LLMs) with reinforcement learning (RL) by treating the LLM as a planner and the RL agent as a controller. It formalizes this hybrid setup as a Goal-Augmented Markov Decision Process and proves that using the LLM’s per‑state progress score as a bounded potential function preserves the optimal policy set, even if the LLM scores are inaccurate. The authors validate their theoretical result with numerical experiments on a small MDP, testing four potential configurations, including an adversarial case with a potential scaled twenty times the base reward.

By Christophe D. Hounwanou, John Emeka Eze, Ya\'e U. Gaba
arXiv Machine Learning
Jul 1

End-to-End Efficient RL for Linear Bellman Complete MDPs with Deterministic Transitions

arXiv:2603. 23461v2 Announce Type: replace Abstract: We study reinforcement learning (RL) with linear function approximation in Markov Decision Processes (MDPs) satisfying \emph{linear Bellman completeness} -- a fundamental setting where the Bellman backup of any linear value function remains linear.

By Zakaria Mhammedi, Alexander Rakhlin, Nneka Okolo