Jingchu Gai
Also known as 盖景初
Jingchu Gai is a machine learning researcher whose work has moved from the expressive power of graph neural networks to reinforcement learning for large language models. As a mathematics undergraduate at Peking University from 2021 to 2025, they coauthored “Beyond Weisfeiler-Lehman: A Quantitative Framework for GNN Expressiveness”, which introduced homomorphism expressivity and received an Outstanding Paper Honorable Mention at ICLR 2024. A follow-up on spectral invariant GNNs appeared at ICLR 2025, and a paper on robust multi-agent reinforcement learning appeared at ICML 2025. In 2026, they published two ICML papers on reinforcement learning for language models and coauthored an LLM system that raised the certified lower bound of the Steiner ratio to 0.8559. They are a PhD student in the Machine Learning Department at Carnegie Mellon University, advised by Andrej Risteski and Aditi Raghunathan.
Timeline
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2021–2025
Mathematics at Peking University
They study mathematics in Peking University's School of Mathematical Sciences from 2021 to 2025 and earn a B.S., advised by Liwei Wang. Their undergraduate research covers graph representation learning and GNN expressiveness.
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January 2024
Homomorphism expressivity of GNNs
They coauthor “Beyond Weisfeiler-Lehman: A Quantitative Framework for GNN Expressiveness” with Bohang Zhang, Yiheng Du, Qiwei Ye, Di He and Liwei Wang, posted in January 2024. The paper introduces homomorphism expressivity, a measure of how well a graph neural network counts graphs under homomorphism.
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2024
An ICLR honorable mention
The paper is presented as an oral at ICLR 2024, where it receives an Outstanding Paper Honorable Mention. The awards committee names 5 Outstanding Paper winners and 11 Honorable Mentions in total.
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2025
Spectral invariant GNNs at ICLR
They publish “Homomorphism Expressivity of Spectral Invariant Graph Neural Networks” at ICLR 2025, with Yiheng Du, Bohang Zhang, Haggai Maron and Liwei Wang. The paper proves that spectral invariant GNNs can homomorphism-count exactly a class of tree-like graphs called parallel trees.
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2025
Robust multi-agent reinforcement learning
They coauthor “Breaking the Curse of Multiagency in Robust Multi-Agent Reinforcement Learning” with Laixi Shi, Eric Mazumdar, Yuejie Chi and Adam Wierman, published at ICML 2025. The paper studies distributionally robust Markov games, where agents optimize worst-case performance when game dynamics shift within an uncertainty set.
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January 2026
Language models and the Steiner ratio
They coauthor “Towards Solving the Gilbert-Pollak Conjecture via Large Language Models” with Yisi Ke, Tianyu Huang, Yankai Shu, Di He and Liwei Wang, submitted in January 2026. The system has language models write geometric lemmas as executable code and establishes a certified lower bound of 0.8559 for the Steiner ratio, up from 0.824. The paper is published at ICML 2026.
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2026
LLM reasoning papers at ICML
They publish two ICML 2026 papers on reinforcement learning for language models, as first author. “Differential Smoothing Mitigates Sharpening and Improves LLM Reasoning” explains why RL fine-tuning loses output diversity and improves Pass@1 and Pass@k, with gains of up to 6.7% on AIME24. “Demystifying Entropy Control in LLM RL Training” derives a dynamic scheduling method that adjusts the entropy coefficient as training evolves.
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Since 2025
PhD at Carnegie Mellon
They begin a PhD in the Machine Learning Department at Carnegie Mellon University in 2025, advised by Andrej Risteski and Aditi Raghunathan. Their current research aims at building reliable foundation models, with interests in LLM reasoning and post-training.
Career
Education
- 2025Peking UniversityB.S.
- From 2025Carnegie Mellon UniversityPhD
Sources and credits
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- Jingchu Gai
- [2401.08514] Beyond Weisfeiler-Lehman: A Quantitative Framework for GNN Expressiveness
- ICLR 2024 Awards
- ICLR 2024 Outstanding Paper Awards – ICLR Blog
- Homomorphism Expressivity of Spectral Invariant Graph Neural Networks
- Breaking the Curse of Multiagency in Robust Multi-Agent Reinforcement Learning
- [2601.22365] Towards Solving the Gilbert-Pollak Conjecture via Large Language Models
- Differential Smoothing Mitigates Sharpening and Improves LLM Reasoning
- Demystifying Entropy Control in LLM RL Training: Theoretical Analysis and Dynamic Scheduling