ResearchResearch paperRetrieval, RAG & Search · Reinforcement Learning · Large Language Models1 source · Oct 20, 2026

RANGER: Retrieval Agent for Navigating Graphs with Semantic Evaluation Rewards

The integration of Large Language Models and Reinforcement Learning offers a promising direction for complex sequential decision-making tasks, such as multi-hop question answering over knowledge graphs.

Key points

  • This paper introduces a novel hybrid approach in which an LLM serves as a mentor to an RL agent during training by providing dense, semantically informed reward signals.
  • The RL agent, built on a Transformer-based policy and trained with Group Relative Policy Optimization, learns to navigate a knowledge graph to retrieve relevant information.
  • We integrate this Retrieval Agent for Navigating Graphs with Semantic Evaluation Rewards (RANGER) into a complete question-answering pipeline and evaluate it on the open question answering datasets.
  • Experimental results show that the proposed approach outperforms both a baseline retrieval-augmented system with classical graph search and one using an RL agent trained with heuristic rewards, achieving a significant increase in NLP metrics and LLM-as-a-Judge scores.

Sources (1)

  • [1]RANGER: Retrieval Agent for Navigating Graphs with Semantic Evaluation Rewards
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 20, 10:53 AM
    The integration of Large Language Models and Reinforcement Learning offers a promising direction for complex sequential decision-making tasks, such as multi-hop question answering over knowledge graphs.
    This paper introduces a novel hybrid approach in which an LLM serves as a mentor to an RL agent during training by providing dense, semantically informed reward signals.

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