Caijun Xu

Fudan University & SII

Alex Research

Advisor: Prof. Yixin Cao

xxcaijun@gmail.com

Hi, I’m Caijun Xu (徐才峻) — a Ph.D. student at Fudan University & SII, working with Prof. Yixin Cao in Alex Research.

My research centers on data synthesis and reasoning for large language models, including reinforcement learning for multi-step reasoning, trajectory generation, and verifier & feedback design. Before my Ph.D., I received a B.Eng. from Beihang University (BUAA), where I worked on graph neural networks and knowledge graphs for recommendation.

Feel free to reach out — I’m always happy to chat about reasoning, RL, and synthetic-data pipelines. You can also find me on Google Scholar and GitHub.

research interests

LLM Reasoning Reinforcement Learning Synthetic Data Verifier & Feedback Knowledge Graphs Recommender Systems

highlights

Paper SCALER: Synthetic Scalable Adaptive Learning Environment for Reasoning accepted to ACL 2026 Findings.
Paper KG-based recommendation paper accepted to CIKM 2024.
Medal ICPC Asia Regional (Xi'an & Jinan) and CCPC Silver (Harbin) medals.

news

May 04, 2026	📄🎉 SCALER: Synthetic Scalable Adaptive Learning Environment for Reasoning — accepted to ACL 2026 Findings.
Oct 20, 2024	📄🎉 Exploring High-Order User Preference with Knowledge Graph for Recommendation — accepted to CIKM 2024 (short paper).
Dec 03, 2023	🥉 Won ICPC Bronze Medal (Jinan).
Nov 05, 2023	🥈 Won CCPC Silver Medal (Harbin).
Oct 22, 2023	🥉 Won ICPC Bronze Medal (Xi’an).

selected publications

ACL’26 Findings

SCALER: Synthetic Scalable Adaptive Learning Environment for Reasoning

Caijun Xu, Changyi Xiao, Zhongyuan Peng, and 2 more authors

In Findings of the Association for Computational Linguistics: ACL 2026, 2026

arXiv Bib

@inproceedings{xu2026scaler,
  title = {{SCALER: Synthetic Scalable Adaptive Learning Environment for Reasoning}},
  author = {Xu, Caijun and Xiao, Changyi and Peng, Zhongyuan and Wang, Xinrun and Cao, Yixin},
  booktitle = {Findings of the Association for Computational Linguistics: {ACL} 2026},
  year = {2026},
  url = {https://arxiv.org/abs/2601.04809},
}

CIKM’24

Exploring High-Order User Preference with Knowledge Graph for Recommendation

Caijun Xu, Fuwei Zhang, Zhao Zhang, and 2 more authors

In Proceedings of the 33rd ACM International Conference on Information and Knowledge Management, 2024

Bib

@inproceedings{xu2024exploring,
  title = {{Exploring High-Order User Preference with Knowledge Graph for Recommendation}},
  author = {Xu, Caijun and Zhang, Fuwei and Zhang, Zhao and Zhuang, Fuzhen and Liu, Rui},
  booktitle = {Proceedings of the 33rd {ACM} International Conference on Information and Knowledge Management},
  pages = {4138--4142},
  year = {2024},
  url = {https://doi.org/10.1145/3627673.3679921},
}