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arXiv research

A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,695 papers · 148 categories

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4385128170 · Jun 202019922001200920172026
48 results for Sparse MDP

New algorithm learns sparse linear MDPs with polynomial interactions, improving sample complexity.

problem Learning optimal policies in sparse linear MDPs with limited interactions and unknown features.
method Developed a polynomial-time algorithm using feature selection and emulator for sparse linear MDPs.
result First polynomial-time algorithm for learning near-optimal policies in k-sparse linear MDPs.

New method approximates POMDPs with PB-MDPs, providing error bounds and practical algorithms.

problem Difficulty in solving POMDPs with continuous or hybrid state and observation spaces.
method Bounding particle filtering error and adapting MDP algorithms to POMDPs.
result General theory and practical algorithms for POMDPs with no direct dependence on state and observation space sizes.

Markov Decision Processes (MDPs) are a mathematical framework for modeling sequential decision making under uncertainty. The classical approaches for solving MDPs are well known and have been widely studied, some of which rely on approximation techniques to solve MDPs with large state space and/or action space. However…

2018-05-08abs ↗pdf ↗

Study shows high-dimensional sparse RL hardness and Lasso Q-iteration's nearly dimension-free regret.

problem Hardness of online sparse reinforcement learning in high-dimensional MDPs.
method Lower bound construction and Lasso fitted Q-iteration analysis.
result Lasso Q-iteration achieves nearly dimension-free regret of O~(s2/3N2/3)\tilde{O}(s^{2/3}N^{2/3}) with oracle access to a good exploratory policy.

We propose an algorithm for deterministic continuous Markov Decision Processes with sparse rewards that computes the optimal policy exactly with no dependency on the size of the state space. The algorithm has time complexity of O(R3×A2)O( |R|^3 \times |A|^2 ) and memory complexity of O(R×A)O( |R| \times |A| ), where R|R| is the…

2018-05-17abs ↗pdf ↗

UCB-TQL learns from multiple tasks with shared dynamics and adapts to task-specific variations.

problem Transfer reinforcement learning with composite MDPs where tasks share core dynamics but have sparse differences.
method UCB-TQL, a novel transfer RL algorithm for composite MDPs.
result Achieved a regret bound of ildeO(eH5N) ilde{O}(\sqrt{eH^5N}) that scales independently of the ambient dimension.

A new method for estimating joint value functions in multi-scene reinforcement learning.

problem High variance in samples for policy gradient computations in multi-scene environments.
method Sparse attention mechanism over multiple value function hypotheses to approximate the true joint value function.
result Significant improvements in reward scores and enhanced navigation efficiency across OpenAI ProcGen environments.

We propose an actor-critic, model-free, and online Reinforcement Learning (RL) framework for continuous-state continuous-action Markov Decision Processes (MDPs) when the reward is highly sparse but encompasses a high-level temporal structure. We represent this temporal structure by a finite-state machine and construct …

2019-09-23abs ↗pdf ↗

Kernel-UCBVI algorithm balances exploration and exploitation in metric state-action spaces.

problem Exploration-exploitation dilemma in finite-horizon reinforcement learning with metric state-action spaces.
method Kernel-UCBVI, leveraging smoothness and kernel estimators of rewards and transitions.
result First regret bound for kernel-based RL using smoothing kernels, O(H3K2d/(2d+1))O(H^3 K^{2d/(2d+1)}).

ETGL-DDPG improves DDPG for sparse reward control with new exploration and replay techniques.

problem Sparse reward continuous control in reinforcement learning.
method Introduces εtεt-greedy search and GDRB framework for efficient exploration and reward use.
result ETGL-DDPG outperforms DDPG and other methods on sparse-reward continuous benchmarks.

Off-policy evaluation for MNAR rewards in MDPs

problem Off-policy evaluation in MDPs with MNAR rewards
method Formalizing a reward-dependent propensity model and using future states as shadow variables
result Proposed an Fitted-Q-Evaluation-style estimator that propagates recovered rewards while allowing target policies to depend on past missingness indicators

Humans achieve efficient learning by relying on prior knowledge about the structure of naturally occurring tasks. There is considerable interest in designing reinforcement learning (RL) algorithms with similar properties. This includes proposals to learn the learning algorithm itself, an idea also known as meta learnin…

2019-05-15abs ↗pdf ↗

We study the sparse entropy-regularized reinforcement learning (ERL) problem in which the entropy term is a special form of the Tsallis entropy. The optimal policy of this formulation is sparse, i.e.,~at each state, it has non-zero probability for only a small number of actions. This addresses the main drawback of the …

2018-02-10abs ↗pdf ↗

We study Exo-MDPs to reduce sample complexity in reinforcement learning.

problem Reducing sample complexity in reinforcement learning for structured MDPs.
method Introducing Exo-MDPs and proving structural equivalence to linear mixture MDPs, establishing regret bounds.
result Proved O(H3/2dK)O(H^{3/2}d\sqrt{K}) regret bound for Exo-MDPs, matching lower bounds.

Improved exploration methods for reinforcement learning with reduced sample complexity.

problem Challenges in reinforcement learning exploration in unknown environments.
method Proposed game-theoretic and trajectory entropy algorithms with improved sample complexity.
result Established statistical advantage of entropy-regularized MDPs for exploration and reduced sample complexity.

We consider large-scale Markov decision processes (MDPs) with parameter uncertainty, under the robust MDP paradigm. Previous studies showed that robust MDPs, based on a minimax approach to handle uncertainty, can be solved using dynamic programming for small to medium sized problems. However, due to the "curse of dimen…

2013-06-26abs ↗pdf ↗

Optimizes learning policies in MDPs with weakly communicating structure.

problem Learning optimal policies in weakly communicating MDPs with generative model.
method Span-based approach, reducing to discounted MDPs for analysis.
result First minimax optimal sample complexity bound for weakly communicating MDPs.

New method removes oracle and reduces memory usage for robust MDPs.

problem Applying robust MDPs in practice due to model estimation and oracle requirements.
method Transformed robust MDPs into an alternative form allowing stochastic gradient methods and model-free approach.
result Sample-efficient algorithm with lower storage requirement and no oracle.

DeepAveragers solves offline RL by solving derived MDPs from static data.

problem Offline reinforcement learning with limited data.
method Solves derived non-parametric MDPs (DAC-MDPs) using deep representations and costs for under-represented parts.
result The approach can lower-bound performance and scale to complex offline RL problems.

New RL method learns to skip states in linearly qπq^π-realizable MDPs, simplifying to linear MDPs.

problem Online RL in episodic MDPs with linearly qπq^π-realizable action-values.
method Derives a novel algorithm that learns to skip states and applies a linear MDP algorithm.
result First polynomial-sample-complexity online RL algorithm for linearly qπq^π-realizable MDPs.

Efficiently plans large MDPs with weak function approximations.

problem Planning in large MDPs with limited function approximation capabilities.
method Uses linear value function approximation with weak requirements and a generative oracle.
result Produces almost-optimal actions for any state with polynomial computation time.

Practical reinforcement learning problems are often formulated as constrained Markov decision process (CMDP) problems, in which the agent has to maximize the expected return while satisfying a set of prescribed safety constraints. In this study, we propose a novel simulator-based method to approximately solve a CMDP pr…

2019-09-20abs ↗pdf ↗

The paper addresses statistical estimation in MDPs with confounders using instrumental variables.

problem Statistical estimation of value functions in MDPs with unobservable confounders.
method Two-stage estimator based on instrumental variables for confounded linear MDPs.
result Established statistical properties of the two-stage estimator, including error bounds and asymptotic normality.

Paper proposes efficient sample collection strategy for RL.

problem Balancing exploration and exploitation in reinforcement learning.
method Decoupled approach with objective-specific and objective-agnostic strategies.
result Improved or novel sample complexity guarantees for various RL settings.

Improved regret bound for MNL MDPs with variance-aware approach.

problem Optimal reinforcement learning for MNL MDPs with structured variance.
method Introducing a problem-dependent constant measuring average variance, proposing an algorithm with improved regret bound.
result Minimax optimal regret bound of O(dH2σˉTT)O(dH^2\barσ_T\sqrt{T}) for structured MDPs.

This work uses action equivariance to learn structured latent spaces for reinforcement learning.

problem Learning structured latent spaces for reinforcement learning.
method Introduced a contrastive loss function to enforce action equivariance on learned representations.
result Optimal policies in the abstract MDP can be successfully lifted to the original MDP.

A new parallel algorithm for learning optimal policies in MDPs with low communication costs.

problem Learning optimal policies for infinite-horizon MDPs.
method Primal-Dual Stochastic Mirror Descent for convex programming problems with inexact constraints.
result First parallel algorithm for average-reward MDPs with generative model and low communication costs.

It has recently been shown that if feedback effects of decisions are ignored, then imposing fairness constraints such as demographic parity or equality of opportunity can actually exacerbate unfairness. We propose to address this challenge by modeling feedback effects as Markov decision processes (MDPs). First, we prop…

2019-01-24abs ↗pdf ↗

The paper introduces MDP homomorphic networks for faster reinforcement learning.

problem Current reinforcement learning approaches do not exploit symmetries in the joint state-action space.
method Equivariant neural networks with group-structured symmetries (reflections, rotations).
result MDP homomorphic networks converge faster than unstructured baselines on various tasks.

New RL approach tackles non-linear MDPs without linear assumptions.

problem Sample efficiency in RL for complex, nonlinear MDPs with continuous states.
method Introduces EPW condition to relax linear structure requirements; provides sample-efficient RL algorithm.
result EPW condition allows solving MDPs without linear assumptions, including Atari games.