Yitong Yao

Author directory

2026

Group-based reinforcement learning typically relies on coarse outcome-level signals, such as group accuracy or variance, for data selection or replay. Yet in multi-turn tool-use rollout groups, these signals miss structural differences between successful and failed trajectories: a failure may diverge into an unrelated tool chain or differ from a successful trajectory only at a local decision. We therefore introduce Group Structural Proximity (GSP), which measures failed-to-successful rollout alignment within a group using tool dependency graphs induced by tool calls and argument flow. A controlled diagnostic study with outcome-statistics-matched subsets further shows that GSP captures distinct learning dynamics: high-GSP data drives localized policy refinement, while low-GSP data induces broader policy movement and higher-entropy exploration. This positions GSP as an effective metric on the exploration–exploitation tradeoff. Building on this insight, we introduce Proximity-Guided Policy Optimization (PGPO), which considers replay buffers with high- and low- GSP under an Exploration-to-Refinement Schedule (ERS) for group-based training. On 𝜏2-Bench and ACEBench Agent, PGPO improves sample efficiency and downstream tool-use performance, demonstrating the benefit of structure-aware group comparison in multi-turn tool-use reinforcement learning.

2025

In this paper, we present a novel pipeline for the XLLM Shared Task-III: Large Language Model for Structural Reasoning (LLM-SR). Our pipeline addresses key challenges in automatic process-reward training data construction, such as high manual annotation costs, limited accuracy of large models in structured data processing, and dependency on auxiliary information for validation. To overcome these limitations, we first decompose the construction process into extraction and validation phases. Leveraging model-generated annotations, we produce pseudo-labeled data and iteratively refine model performance. Second, by analyzing structured data patterns, we encode structural constraints into a rule-based module and fine-tune the model with Gradient Reward Policy Optimization (GRPO), significantly improving structured data extraction success rates. Finally, we train the model to generate critical responses that assess evidence-conclusion relationships, thus enhancing validation reliability. Experimental results demonstrate that our pipeline outperforms models with an order of magnitude more parameters and achieves the first position on the task.

2024

In this paper, we present TeleChat, a collection of large language models (LLMs) with parameters of 7 billion and 12 billion. TeleChat is initially pretrained on an extensive corpus containing a diverse collection of texts from both English and Chinese languages, encompassing trillions of tokens. Subsequently, the model undergoes fine-tuning to align with human preferences, following a detailed methodology that we describe. We evaluate the performance of TeleChat on various tasks, including general dialogue generation, language understanding, mathematics, reasoning, code generation, and knowledge-based question answering. Our findings indicate that TeleChat achieves state-of-the-art performance to other open-source models of similar size across a wide range of public benchmarks. To support future research and applications utilizing LLMs, we release the fine-tuned model checkpoints of TeleChat-7B and TeleChat-12B, along with code and a portion of our filtered high-quality pretraining data, to the public community.