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Main Authors: Guo, Yiran, Qiao, Zhongjian, Xie, Yingqi, Liu, Jie, Ye, Dan, Zhang, Ruiqing, Qiu, Shuang, Xu, Lijie
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.14169
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author Guo, Yiran
Qiao, Zhongjian
Xie, Yingqi
Liu, Jie
Ye, Dan
Zhang, Ruiqing
Qiu, Shuang
Xu, Lijie
author_facet Guo, Yiran
Qiao, Zhongjian
Xie, Yingqi
Liu, Jie
Ye, Dan
Zhang, Ruiqing
Qiu, Shuang
Xu, Lijie
contents Effective exploration is a key challenge in reinforcement learning for large language models: discovering high-quality trajectories within a limited sampling budget from the vast natural language sequence space. Existing methods face notable limitations: GRPO samples exclusively from the root, saturating high-probability trajectories while leaving deep, error-prone states under-explored. Tree-based methods blindly disperse budgets across trivial or unrecoverable states, causing sampling dilution that fails to uncover rare correct suffixes and destabilizes local baselines. To address this, we propose Deep Dense Exploration (DDE), a strategy that focuses exploration on $\textit{pivots}$-deep, recoverable states within unsuccessful trajectories. We instantiate DDE with DEEP-GRPO, which introduces three key innovations: (1) a lightweight data-driven utility function that automatically balances recoverability and depth bias to identify pivot states; (2) local dense resampling at each pivot to increase the probability of discovering correct subsequent trajectories; and (3) a dual-stream optimization objective that decouples global policy learning from local corrective updates. Experiments on mathematical reasoning benchmarks demonstrate that our method consistently outperforms GRPO, tree-based methods, and other strong baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2602_14169
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Deep Dense Exploration for LLM Reinforcement Learning via Pivot-Driven Resampling
Guo, Yiran
Qiao, Zhongjian
Xie, Yingqi
Liu, Jie
Ye, Dan
Zhang, Ruiqing
Qiu, Shuang
Xu, Lijie
Machine Learning
Artificial Intelligence
Computation and Language
Effective exploration is a key challenge in reinforcement learning for large language models: discovering high-quality trajectories within a limited sampling budget from the vast natural language sequence space. Existing methods face notable limitations: GRPO samples exclusively from the root, saturating high-probability trajectories while leaving deep, error-prone states under-explored. Tree-based methods blindly disperse budgets across trivial or unrecoverable states, causing sampling dilution that fails to uncover rare correct suffixes and destabilizes local baselines. To address this, we propose Deep Dense Exploration (DDE), a strategy that focuses exploration on $\textit{pivots}$-deep, recoverable states within unsuccessful trajectories. We instantiate DDE with DEEP-GRPO, which introduces three key innovations: (1) a lightweight data-driven utility function that automatically balances recoverability and depth bias to identify pivot states; (2) local dense resampling at each pivot to increase the probability of discovering correct subsequent trajectories; and (3) a dual-stream optimization objective that decouples global policy learning from local corrective updates. Experiments on mathematical reasoning benchmarks demonstrate that our method consistently outperforms GRPO, tree-based methods, and other strong baselines.
title Deep Dense Exploration for LLM Reinforcement Learning via Pivot-Driven Resampling
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2602.14169