arXiv Statistics ML

Temporal difference learning adapts to incomplete coverage: an oracle inequality over subgraphs

The paper demonstrates that ordinary temporal difference (TD) learning in a tabular setting automatically combines the asymptotic efficiency of TD with the visitation requirements of Monte Carlo (MC) methods. By introducing the subgraph Bellman variance—a measure of variance arising from bootstrapping within a subgraph and rollouts outside it—the authors prove a non‑asymptotic oracle inequality: the mean squared error of full TD is bounded by this variance divided by the sample size for every sufficiently covered subgraph containing the target, plus a higher‑order remainder that depends only on that subgraph. Importantly, the algorithm does not need to be supplied with any subgraph, allowing TD to adapt to incomplete coverage without global visitation guarantees.

arXiv Machine Learning
Sep 18

Model-based Bootstrap for Offline Policy Evaluation in Tabular Reinforcement Learning

The paper introduces a model-based bootstrap framework for uncertainty quantification in offline policy evaluation (OPE) within finite-horizon, time-inhomogeneous Markov decision processes. Unlike traditional bootstrap methods that resample entire episodes, this approach regenerates trajectories from an estimated MDP, enabling use of diverse offline data formats such as complete trajectories, transition-level observations, and trajectory fragments. The authors prove bootstrap distributional consistency, asymptotically valid confidence intervals, and consistent variance estimation, and demonstrate through simulations that the method yields tighter confidence intervals and more accurate variance estimates compared to existing techniques.

By Weiwei Wang, Yuqiang Li, Xianyi Wu, Bingyi Jing
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
Hugging Face Trending Papers
Sep 24

A Contraction Framework for Stochastic Operators with Bootstrapping: Application to TD Learning

The paper introduces a contraction framework for stochastic operators that incorporates bootstrapping, where a variable is updated using a frozen copy as a target that is refreshed every $K$ steps. By modeling the sampled update as a stochastic operator, the authors derive a finite‑time bound for i.i.d. samples that applies to any target‑update period and does not require gradient structure or uniformly bounded sampling error. The framework shows that the iterates converge geometrically in root mean square to a ball around the fixed point, with the error floor scaling with the step size, and it generalizes existing deterministic and stochastic‑gradient bounds.

arXiv Machine Learning
Jul 8

Model-based Bootstrap of Controlled Markov Chains

arXiv:2605. 12410v2 Announce Type: replace-cross Abstract: We propose and analyze a model-based bootstrap for transition kernels in finite controlled Markov chains (CMCs) with possibly nonstationary or history-dependent control policies, a setting that arises naturally in offline reinforcement learning (RL) when the behavior policy generating the data is unknown.

By Ziwei Su, Imon Banerjee, Diego Klabjan