Jiancong Xiao

Welcome to my homepage! I am a tenure-track Assistant Professor in the Department of Computer Science at the National University of Singapore (NUS).

Previously, I was a postdoctoral researcher at the University of Pennsylvania, where I worked with Prof. Qi Long and Prof. Weijie J. Su. I obtained my Ph.D. from The Chinese University of Hong Kong, Shenzhen, where I was advised by Prof. Zhi-Quan (Tom) Luo and worked closely with Prof. Ruoyu Sun. Before starting my doctoral studies, I spent two years working in finance. I received my M.S. degree from The Chinese University of Hong Kong and my Bacholar’s degree from Sun Yat-sen University.

Research Interest: I am broadly interested in learning theory, statistics and optimization, with a focus on establishing foundations for responsible and trustworthy machine learning models. My recent research focuses on mathematical and statistical topics in large language models (LLMs).

1. Theoretical Foundations for LLM: Analyzing algorithmic biases in preference alignment methods, developing preference alignment algorithms, exploring game-theoretic approaches to alignment, and investigating alignment from the perspective of social choice theory.

2. LLM Training and Fine-Tuning: Establishing theoretical foundations for fine-tuning and post-training algorithms. Addressing calibration issues in LLMs.

3. Adversarial Robustness: Developing theoretical frameworks for understanding adversarial examples, robust overfitting, and adversarially robust generalization.

4. Classical Learning Theory: Studying Generalization (Rademacher complexity, Uniform stability, Pac-Bayes), Optimization (non-convex, non-smooth problem).

[Announcement] I am actively looking for PhD students for Fall 2027, as well as research assistants and research interns. If you are interested, please feel free to reach out via email.