Frequency-Uniform Log-Regret Reinforcement Learning for Diffusions
Abstract
High-frequency control problems are often studied through time discretization, but refining the timestep δ increases the discrete horizon H=T/δ and can make standard finite-horizon regret guarantees deteriorate even when the physical horizon T is fixed. We study episodic value-based reinforcement learning for Euler discretizations of controlled diffusions. The performance is measured as the cumulative regret over K episodes relative to the optimal policy of the corresponding Euler model. Under stability and regularity conditions on value function gradients, Bellman residual derivatives, and fitted critics, we prove an 𝒪(log K) regret bound with constants uniform in δ. For dynamics with drift linear in unknown parameters and unknown constant diffusion covariance, we verify localized versions of these conditions for a constrained, model-based controlled-diffusion fitted-Q algorithm (CD-FQ) and obtain high-probability 𝒪(log Kloglog K) regret for fixed and finite T, again with constants uniform in δ.
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BibTeX
@misc{blanchet2026frequencyuniform,
title = {{Frequency-Uniform Log-Regret Reinforcement Learning for Diffusions}},
author = {Jose Blanchet and Lutong Hao and Renyuan Xu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.36758},
eprint = {2610.36758},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.36758},
}
RIS
TY - UNPB
TI - Frequency-Uniform Log-Regret Reinforcement Learning for Diffusions
AU - Jose Blanchet
AU - Lutong Hao
AU - Renyuan Xu
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.36758
UR - https://arxiv.org/abs/2610.36758
AB - High-frequency control problems are often studied through time discretization, but refining the timestep δ increases the discrete horizon H=T/δ and can make standard finite-horizon regret guarantees deteriorate even when the physical horizon T is fixed. We study episodic value-based reinforcement learning for Euler discretizations of controlled diffusions. The performance is measured as the cumulative regret over K episodes relative to the optimal policy of the corresponding Euler model. Under stability and regularity conditions on value function gradients, Bellman residual derivatives, and fitted critics, we prove an 𝒪(log K) regret bound with constants uniform in δ. For dynamics with drift linear in unknown parameters and unknown constant diffusion covariance, we verify localized versions of these conditions for a constrained, model-based controlled-diffusion fitted-Q algorithm (CD-FQ) and obtain high-probability 𝒪(log Kloglog K) regret for fixed and finite T, again with constants uniform in δ.
ER -