I am a postdoctoral researcher at the IBS Biomedical Mathematics Group (BIMAG).
My research focuses on topological deep learning and higher-order graph neural networks, particularly on symmetric simplicial sets and hypergraphs, with applications to biological and chemical networks.
For a detailed overview of my work and background, please see my [Curriculum Vitae] and [Research Statement].
Email: sjin.choi1 [at] gmail.com / sjinchoi [at] ibs.re.kr
Education
Ph.D. in Mathematics, POSTECH, March 2014 – Feb 2026 (Advisor: Yong-Geun Oh)
B.S. in Mathematics, POSTECH, March 2010 – February 2014
Publications
Journal Articles
G. Kim, S. Choi, and S. Y. Yun, "A mutual information-based framework for enhancing graph neural networks on heterophily," IEEE Access, 2025, doi: 10.1109/ACCESS.2025.3624415.
S. Choi, G. Kim, and Y. G. Oh, "Hypergraph neural sheaf diffusion: A symmetric simplicial set framework for higher-order learning," IEEE Access, vol. 13, pp. 131823--131838, Jul. 2025, doi: 10.1109/ACCESS.2025.3592104.
Workshop Papers
S. Choi, G. Kim, and S. Y. Yun, "Node mutual information: Enhancing graph neural networks for heterophily," in NeurIPS 2023 Workshop: New Frontiers in Graph Learning, 2023. [Online].
Preprints
S. Choi, G. Kim, and S. Y. Yun, "Weisfeiler and Lehman Go Categorical", arXiv preprint arXiv:2602.06787, Feb.2026. [Online].
S. Choi and J. Park, "Cellular sheaf Laplacians on the set of simplices of symmetric simplicial set induced by hypergraph," arXiv preprint arXiv:2411.08458, Nov. 2024. [Online].
Invited talks
Topology, Geometry and Data Analysis (ToGeDA) Mini-Workshop, KAIST, Daejeon, South Korea, Jan 2026, "Expanding the Domains of Topological Deep Learning: Symmetric Simplicial Sets and Graded Posets". Slides (PDF)
Workshop on Mathematical Signal Processing, RWTH Aachen University, Germany, Sep 2025.
Talk: "Symmetric Simplicial Lifting for Hypergraph Learning". Slides (PDF)
Topological Data Analysis and Industrial Mathematics: Bridging Theory and Applications, Kyushu University, Japan, Aug 2025, "Symmetric Simplicial Lifting for Hypergraph Learning". Slides (PDF)
Asia Pacific Seminar on Applied Topology and Geometry, Online, Jan 2025, "Sheaf Laplacians on hypergraphs via symmetric simplicial sets". Slides (PDF)