arXiv Machine Learning

A Continuous-Time Actor-Critic Framework for Jump-Diffusion Controls with Normalizing Flows

The paper introduces a continuous‑time actor‑critic framework for jump‑diffusion control problems, using a time‑inhomogeneous q‑function and occupation measure to derive a policy‑gradient representation that handles time‑dependent drift, volatility, and jump terms. The actor is modeled with conditional normalizing flows, allowing flexible non‑Gaussian continuous‑action policies while maintaining exact likelihoods for entropy regularization. Experiments on linear‑quadratic control, Merton portfolio optimization, and a multi‑agent portfolio game show stable learning, accurate policy approximation, and good scaling with dimension and agent count.

arXiv Machine Learning
Aug 24

Reinforcement Learning for Continuous-Time Jump Markov Decision Processes with Applications to Network Dynamic Pricing

The paper introduces reinforcement learning for Continuous-Time Jump Markov Decision Processes (CTJMDPs) with general discrete state spaces and continuous/discrete actions. It develops entropy‑regularized continuous‑time control and establishes theoretical foundations for q‑learning in this setting, providing model‑free algorithms that outperform naive discretization. Numerical tests on network dynamic pricing demonstrate the method’s ability to learn near‑optimal policies and scale to large networks.

By Huiling Meng, Ningyuan Chen, Xuefeng Gao
arXiv Machine Learning
Jun 30

Entropy Regularized Reinforcement Learning for Zero-Sum Stochastic Differential Games in a Regime-Switching Jump-Diffusion Process

arXiv:2606. 28669v1 Announce Type: new Abstract: To address parameter misspecification and sudden structural environmental changes in conventional stochastic differential game (SDG) frameworks, this paper introduces a distributional control approach that characterizes optimal strategies as probability distributions over actions, conditioned on the continuous state, the discrete regime state, and parameters.

By Congde Hu, Zhuo Jin, Danping Li, Lin Xu
arXiv Machine Learning
Oct 21

Continuous-Time Policy Gradient from Discrete Data: Convergence Analysis and Model-Free Algorithms

The paper introduces a continuous‑time policy gradient framework that works with discrete observation data. It derives performance difference lemmas and policy gradient formulas for randomized and parametrized policies, proving exponential convergence for an entropy‑regularized policy flow and providing explicit convergence bounds for discrete updates. By integrating with PhiBE, the authors create model‑free actor‑critic algorithms that maintain the continuous‑time structure, and demonstrate their effectiveness on both linear‑quadratic and nonlinear robotic control tasks.

By Martin Hernandez, Xinyan Qing, Mo Zhou, Yuhua Zhu
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 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
Jul 7

Adaptive Partitioning and Learning for Stochastic Control of Diffusion Processes

arXiv:2512. 14991v2 Announce Type: replace Abstract: We study reinforcement learning for controlled diffusion processes with unbounded continuous state spaces, bounded continuous actions, and polynomially growing rewards: settings that arise naturally in finance, economics, and operations research.

By Hanqing Jin, Renyuan Xu, Yanzhao Yang
arXiv Machine Learning
Oct 22

A Model-Free Continuous-Time RL Algorithm from Discrete-Time Off-Policy Data with End-to-End Guarantees

The paper introduces a model‑free continuous‑time reinforcement learning algorithm that learns from a fixed batch of discrete‑time off‑policy data. It builds on the PhiBE‑Q framework to create a PhiBE‑PI policy iteration that uses a single state‑action critic, avoiding explicit drift or diffusion estimation. The authors provide a local end‑to‑end suboptimality guarantee under linear function approximation, analyze error propagation from discretization, function approximation, and finite samples, and reveal a bias‑variance trade‑off where finer time discretization can worsen statistical error.

By Chaorui Yao, Yuming Paul Zhang, Lin Yang, Yuhua Zhu
arXiv Machine Learning
Jun 30

Entropy-Regularized Reinforcement Learning for Linear-Quadratic Stackelberg Differential Games in Regime-Switching Diffusion Models

arXiv:2606. 28671v1 Announce Type: new Abstract: Stackelberg differential games (SDGs) provide a powerful framework for hierarchical decision-making in stochastic and continuous-time environments, yet their solution remains computationally challenging due to the complexity of traditional dynamic programming and Hamilton-Jacobi-Bellman-Isaacs (HJBI) methods, especially in high-dimensional systems.

By Congde Hu, Danping Li, Lin Xu, Wenying Xu
arXiv AI
Aug 19

Solving nonconvex Hamilton--Jacobi--Isaacs equations with PINN-based policy iteration

The paper introduces a mesh‑free policy iteration framework that blends classical dynamic programming with physics‑informed neural networks (PINNs) to solve high‑dimensional, nonconvex Hamilton–Jacobi–Isaacs (HJI) equations. The method alternates between solving linear second‑order PDEs under fixed feedback policies and updating controls via pointwise minimax optimization using automatic differentiation. The authors prove local uniform convergence of the value function iterates to the unique viscosity solution under standard Lipschitz and uniform ellipticity assumptions, and demonstrate the approach’s accuracy and scalability in two‑, five‑, and ten‑dimensional stochastic games, outperforming direct PINN solvers.

By Hee Jun Yang, Minjung Gim, Yeoneung Kim