This is the ByteDance IMO paper I heard rumors about recently. They built hybrid systems which uses Lean as well as an LLM. They were able to solve 5/6 problems using the two systems Seed-Prover and Seed-Geometry (which improves weak Lean geometry capabilities). IIUC only Seed-Prover participated offically at IMO and solved 4/6 for a silver medal.
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