arXiv AI By Zishuo Zhao (Alibaba Group), Kai Chen (Alibaba Group), Ao Li (Alibaba Group), Yuan Liu (Alibaba Group)

Turn-level Multiscale Density Ratio Estimation for LLM Agents

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The paper introduces Turn-level Multiscale Density Ratio Estimation (tlm‑DRE), a post‑training technique for large language model agents that assigns varying weights to different turns and employs asymmetric token‑level training based on positive‑negative gaps across multiple turns. Unlike conventional alignment methods such as PPO, DPO, DIL, and GRPO, which mainly target single‑turn tasks, tlm‑DRE is designed for complex multi‑turn reasoning. Experiments on diverse agent benchmarks demonstrate that tlm‑DRE competes with traditional alignment methods and enables LLMs to perform robustly in both in‑domain and out‑of‑domain multi‑turn tasks.

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