# Improved Variance-Aware Confidence Sets for Linear Bandits and Linear Mixture MDP

arXiv: https://arxiv.org/abs/2101.12745 · HTML: https://mlsanity.com/paper/2101.12745/

## Key facts

- Cited by 45 papers in the map (data through 14 Oct 2026).
- Builds on 37 of its 70 references that are in the map.
- First posted on arXiv 29 Jan 2021.

## Builds on (most cited first, 30 of 37)

- [Provably Efficient Reinforcement Learning with Linear Function Approximation](https://mlsanity.com/paper/1907.05388/) (2019)
- [Minimax Regret Bounds for Reinforcement Learning](https://mlsanity.com/paper/1703.05449/) (2017)
- [Is Q-learning Provably Efficient?](https://mlsanity.com/paper/1807.03765/) (2018)
- [Contextual Decision Processes with Low Bellman Rank are PAC-Learnable](https://mlsanity.com/paper/1610.09512/) (2016)
- [Model-Based Reinforcement Learning with Value-Targeted Regression](https://mlsanity.com/paper/2006.01107/) (2020)
- [Provably Efficient Exploration in Policy Optimization](https://mlsanity.com/paper/1912.05830/) (2019)
- [Reinforcement Learning in Feature Space: Matrix Bandit, Kernels, and Regret Bound](https://mlsanity.com/paper/1905.10389/) (2019)
- [Nearly Minimax Optimal Reinforcement Learning for Linear Mixture Markov Decision Processes](https://mlsanity.com/paper/2012.08507/) (2020)
- [Tighter Problem-Dependent Regret Bounds in Reinforcement Learning without Domain Knowledge using Value Function Bounds](https://mlsanity.com/paper/1901.00210/) (2019)
- [Learning Near Optimal Policies with Low Inherent Bellman Error](https://mlsanity.com/paper/2003.00153/) (2020)
- [Provably efficient RL with Rich Observations via Latent State Decoding](https://mlsanity.com/paper/1901.09018/) (2019)
- [Is a Good Representation Sufficient for Sample Efficient Reinforcement Learning?](https://mlsanity.com/paper/1910.03016/) (2019)
- [Almost Optimal Model-Free Reinforcement Learning via Reference-Advantage Decomposition](https://mlsanity.com/paper/2004.10019/) (2020)
- [Improved Optimistic Algorithms for Logistic Bandits](https://mlsanity.com/paper/2002.07530/) (2020)
- [Kinematic State Abstraction and Provably Efficient Rich-Observation Reinforcement Learning](https://mlsanity.com/paper/1911.05815/) (2019)
- [Optimism in Reinforcement Learning with Generalized Linear Function Approximation](https://mlsanity.com/paper/1912.04136/) (2019)
- [Breaking the Sample Size Barrier in Model-Based Reinforcement Learning with a Generative Model](https://mlsanity.com/paper/2005.12900/) (2020)
- [Provably Efficient Reinforcement Learning for Discounted MDPs with Feature Mapping](https://mlsanity.com/paper/2006.13165/) (2020)
- [Sample Complexity of Reinforcement Learning using Linearly Combined Model Ensembles](https://mlsanity.com/paper/1910.10597/) (2019)
- [Is Reinforcement Learning More Difficult Than Bandits? A Near-optimal Algorithm Escaping the Curse of Horizon](https://mlsanity.com/paper/2009.13503/) (2020)
- [On Reward-Free Reinforcement Learning with Linear Function Approximation](https://mlsanity.com/paper/2006.11274/) (2020)
- [Policy Certificates: Towards Accountable Reinforcement Learning](https://mlsanity.com/paper/1811.03056/) (2018)
- [Logarithmic Regret for Reinforcement Learning with Linear Function Approximation](https://mlsanity.com/paper/2011.11566/) (2020)
- [On Oracle-Efficient PAC RL with Rich Observations](https://mlsanity.com/paper/1803.00606/) (2018)
- [Optimal Best-arm Identification in Linear Bandits](https://mlsanity.com/paper/2006.16073/) (2020)
- [Exponential Lower Bounds for Planning in MDPs With Linearly-Realizable Optimal Action-Value Functions](https://mlsanity.com/paper/2010.01374/) (2020)
- [Instance-Wise Minimax-Optimal Algorithms for Logistic Bandits](https://mlsanity.com/paper/2010.12642/) (2020)
- [An Empirical Process Approach to the Union Bound: Practical Algorithms for Combinatorial and Linear Bandits](https://mlsanity.com/paper/2006.11685/) (2020)
- [Regret Minimization for Reinforcement Learning by Evaluating the Optimal Bias Function](https://mlsanity.com/paper/1906.05110/) (2019)
- [Reinforcement Learning with General Value Function Approximation: Provably Efficient Approach via Bounded Eluder Dimension](https://mlsanity.com/paper/2005.10804/) (2020)

## Built on by (most cited first, 30 of 45)

- [Nearly Minimax Optimal Reinforcement Learning for Linear Markov Decision Processes](https://mlsanity.com/paper/2212.06132/) (2022)
- [Computationally Efficient Horizon-Free Reinforcement Learning for Linear Mixture MDPs](https://mlsanity.com/paper/2205.11507/) (2022)
- [Variance-Dependent Regret Bounds for Linear Bandits and Reinforcement Learning: Adaptivity and Computational Efficiency](https://mlsanity.com/paper/2302.10371/) (2023)
- [A Theoretical Analysis of Optimistic Proximal Policy Optimization in Linear Markov Decision Processes](https://mlsanity.com/paper/2305.08841/) (2023)
- [Learning Stochastic Shortest Path with Linear Function Approximation](https://mlsanity.com/paper/2110.12727/) (2021)
- [Variance-Aware Regret Bounds for Stochastic Contextual Dueling Bandits](https://mlsanity.com/paper/2310.00968/) (2023)
- [Sharp Variance-Dependent Bounds in Reinforcement Learning: Best of Both Worlds in Stochastic and Deterministic Environments](https://mlsanity.com/paper/2301.13446/) (2023)
- [Upper and Lower Bounds for Distributionally Robust Off-Dynamics Reinforcement Learning](https://mlsanity.com/paper/2409.20521/) (2024)
- [Batch-Size Independent Regret Bounds for Combinatorial Semi-Bandits with Probabilistically Triggered Arms or Independent Arms](https://mlsanity.com/paper/2208.14837/) (2022)
- [Improved Regret Analysis in Gaussian Process Bandits: Optimality for Noiseless Reward, RKHS norm, and Non-Stationary Variance](https://mlsanity.com/paper/2502.06363/) (2025)
- [Tackling Heavy-Tailed Rewards in Reinforcement Learning with Function Approximation: Minimax Optimal and Instance-Dependent Regret Bounds](https://mlsanity.com/paper/2306.06836/) (2023)
- [Provably Efficient Iterated CVaR Reinforcement Learning with Function Approximation and Human Feedback](https://mlsanity.com/paper/2307.02842/) (2023)
- [Offline Reinforcement Learning with Differentiable Function Approximation is Provably Efficient](https://mlsanity.com/paper/2210.00750/) (2022)
- [Variance-Aware Sparse Linear Bandits](https://mlsanity.com/paper/2205.13450/) (2022)
- [Model-based RL as a Minimalist Approach to Horizon-Free and Second-Order Bounds](https://mlsanity.com/paper/2408.08994/) (2024)
- [How Does Variance Shape the Regret in Contextual Bandits?](https://mlsanity.com/paper/2410.12713/) (2024)
- [Variance-aware robust reinforcement learning with linear function approximation under heavy-tailed rewards](https://mlsanity.com/paper/2303.05606/) (2023)
- [Optimal Horizon-Free Reward-Free Exploration for Linear Mixture MDPs](https://mlsanity.com/paper/2303.10165/) (2023)
- [Randomized Exploration for Reinforcement Learning with Multinomial Logistic Function Approximation](https://mlsanity.com/paper/2405.20165/) (2024)
- [Sample Complexity Characterization for Linear Contextual MDPs](https://mlsanity.com/paper/2402.02700/) (2024)
- [Warm-up Free Policy Optimization: Improved Regret in Linear Markov Decision Processes](https://mlsanity.com/paper/2407.03065/) (2024)
- [Horizon-Free and Variance-Dependent Reinforcement Learning for Latent Markov Decision Processes](https://mlsanity.com/paper/2210.11604/) (2022)
- [Horizon-free Reinforcement Learning in Adversarial Linear Mixture MDPs](https://mlsanity.com/paper/2305.08359/) (2023)
- [Learning Adversarial Low-rank Markov Decision Processes with Unknown Transition and Full-information Feedback](https://mlsanity.com/paper/2311.07876/) (2023)
- [Horizon-Free and Instance-Dependent Regret Bounds for Reinforcement Learning with General Function Approximation](https://mlsanity.com/paper/2312.04464/) (2023)
- [Allocation Stability and Wald Inference under Variance-Aware UCB](https://mlsanity.com/paper/2412.08843/) (2024)
- [Variance-Dependent Regret Lower Bounds for Contextual Bandits](https://mlsanity.com/paper/2503.12020/) (2025)
- [Sharp Gap-Dependent Variance-Aware Regret Bounds for Tabular MDPs](https://mlsanity.com/paper/2506.06521/) (2025)
- [Vector-valued self-normalized concentration inequalities beyond sub-Gaussianity](https://mlsanity.com/paper/2511.03606/) (2025)
- [SPEED: Experimental Design for Policy Evaluation in Linear Heteroscedastic Bandits](https://mlsanity.com/paper/2301.12357/) (2023)

## Abstract (arXiv)

This paper presents new variance-aware confidence sets for linear bandits and linear mixture Markov Decision Processes (MDPs). With the new confidence sets, we obtain the follow regret bounds: For linear bandits, we obtain an tildeO(poly(d)√1 + sumk=1Kσk2) data-dependent regret bound, where d is the feature dimension, K is the number of rounds, and σk2 is the unknown variance of the reward at the k-th round. This is the first regret bound that only scales with the variance and the dimension but no explicit polynomial dependency on K. When variances are small, this bound can be significantly smaller than the tildeThetaleft(d√Kright) worst-case regret bound. For linear mixture MDPs, we obtain an tildeO(poly(d, log H)√K) regret bound, where d is the number of base models, K is the number of episodes, and H is the planning horizon. This is the first regret bound that only scales logarithmically with H in the reinforcement learning with linear function approximation setting, thus exponentially improving existing results, and resolving an open problem in citepzhou2020nearly. We develop three technical ideas that may be of independent interest: 1) applications of the peeling technique to both the input norm and the variance magnitude, 2) a recursion-based estimator for the variance, and 3) a new convex potential lemma that generalizes the seminal elliptical potential lemma.