Li An
Author directory2026
NaturalPRISM: A Natural Language Premise Retrieval Task for Research-level Intermediate Proof States
Harris Proctor | Li An | Austin LaHue | Michael Burr | Vinita Gangaram Jansari | Carlos Toxtli Hernandez | Luis David Garcia Puente | Benjamin E Nye
The Proceedings of the 4th Workshop on Mathematical Natural Language Processing (MathNLP 2026)
Harris Proctor | Li An | Austin LaHue | Michael Burr | Vinita Gangaram Jansari | Carlos Toxtli Hernandez | Luis David Garcia Puente | Benjamin E Nye
The Proceedings of the 4th Workshop on Mathematical Natural Language Processing (MathNLP 2026)
As AI use progresses in research-level mathematics, automated information retrieval systems for constructing relevant prompts are increasingly important. Existing benchmarks and datasets for identifying which prior results are necessary to prove a statement do not align well with current workflows in which a natural language proof is in progress, but it is unclear what the next step(s) should be.
We introduce NaturalPRISM, a benchmark task and dataset containing 1.7 million pairs of intermediate proof states and the premise invoked in the next step of the proof. All pairs are extracted from natural language research-level mathematics papers published on arXiv, and span all 32 subject categories.
We evaluate the effect of fine-tuning retrieval models for domain-specific vs. domain-agnostic use cases, and find that the combination of sufficient training data with alignment between the training and testing distributions allows smaller specialized models to dramatically outperform larger general models.
We introduce NaturalPRISM, a benchmark task and dataset containing 1.7 million pairs of intermediate proof states and the premise invoked in the next step of the proof. All pairs are extracted from natural language research-level mathematics papers published on arXiv, and span all 32 subject categories.
We evaluate the effect of fine-tuning retrieval models for domain-specific vs. domain-agnostic use cases, and find that the combination of sufficient training data with alignment between the training and testing distributions allows smaller specialized models to dramatically outperform larger general models.
Speculate While You Reason: Teaching Agents to Predict Their Next Tool Call via Joint Agent–Speculator RL
Jiabao Ji | Yujian Liu | Li An | Rohit Jain | Gungor Polatkan | Siyu Zhu | Shiyu Chang
Findings of the Association for Computational Linguistics: EMNLP 2026
Jiabao Ji | Yujian Liu | Li An | Rohit Jain | Gungor Polatkan | Siyu Zhu | Shiyu Chang
Findings of the Association for Computational Linguistics: EMNLP 2026
Large language model agents often spend substantial wall-clock time waiting for tool call results. Tool-call speculation can hide this latency by predicting and pre-executing an agent’s next tool call if the prediction matches the agent’s eventual tool call, but existing speculators are typically separate draft models or cached traces that are poorly aligned with the deployed agent’s own behavior. We identify this speculator–agent gap and show that the target agent itself is a strong next-call speculator. This points to a simpler design: unifying the agent and speculator within the same model. In this paper, we introduce the self-speculating agent, a single model that both solves tasks in agent mode and predicts its next tool call from partial trajectories in speculator mode, fully reusing prefix KV cache. To enable this dual-mode agent without degrading performance, we propose a joint agent-speculator reinforcement learning method, which derives speculation targets from the agent’s own rollouts and alternates agent and speculator updates. Across agentic search QA and conversational tool-use agentic tasks, our method improves average next tool-call Hit@1 from 44.1 to 61.2 for Qwen3-4B and from 48.9 to 66.3 for Qwen3.5-4B, while preserving agent task success.
A Reinforcement Learning Framework for Robust and Secure LLM Watermarking
Li An | Yujian Liu | Yepeng Liu | Yuheng Bu | Yang Zhang | Shiyu Chang
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Li An | Yujian Liu | Yepeng Liu | Yuheng Bu | Yang Zhang | Shiyu Chang
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Watermarking has emerged as a promising solution for tracing and authenticating text generated by large language models (LLMs). A common approach to LLM watermarking is to construct a green/red token list and assign higher or lower generation probabilities to the corresponding tokens, respectively. However, most existing watermarking algorithms rely on heuristic green/red token list designs, as directly optimizing the list design with techniques such as reinforcement learning (RL) comes with several challenges. First, desirable watermarking involves multiple criteria, i.e., detectability, text quality, robustness against removal attacks, and security against spoofing attacks. Directly optimizing for these criteria introduces many partially conflicting reward terms, leading to an unstable convergence process. Second, the vast action space of green/red token list choices is susceptible to reward hacking. In this paper, we propose an end-to-end RL framework for robust and secure LLM watermarking. Our approach adopts an anchoring mechanism for reward terms to ensure stable training and introduces additional regularization terms to prevent reward hacking. Experiments on standard benchmarks with two backbone LLMs show that our method achieves a state-of-the-art trade-off across all criteria, with notable improvements in resistance to spoofing attacks without degrading other criteria.
2023
MAX-ISI System at WMT23 Discourse-Level Literary Translation Task
Li An | Linghao Jin | Xuezhe Ma
Proceedings of the Eighth Conference on Machine Translation
Li An | Linghao Jin | Xuezhe Ma
Proceedings of the Eighth Conference on Machine Translation
This paper describes our translation systems for the WMT23 shared task. We participated in the discourse-level literary translation task - constrained track. In our methodology, we conduct a comparative analysis between the conventional Transformer model and the recently introduced MEGA model, which exhibits enhanced capabilities in modeling long-range sequences compared to the traditional Transformers. To explore whether language models can more effectively harness document-level context using paragraph-level data, we took the approach of aggregating sentences into paragraphs from the original literary dataset provided by the organizers. This paragraph-level data was utilized in both the Transformer and MEGA models. To ensure a fair comparison across all systems, we employed a sentence-alignment strategy to reverse our translation results from the paragraph-level back to the sentence-level alignment. Finally, our evaluation process encompassed sentence-level metrics such as BLEU, as well as two document-level metrics: d-BLEU and BlonDe.