Jacob Tsimerman is joining OpenAI to work in its safety division. He disclosed the move at a July 23 press conference shortly after receiving the 2026 Fields Medal, saying he would start at OpenAI very soon, The Washington Post reported. OpenAI has not published a more specific job title.
Tsimerman is taking leave from his professorship at the University of Toronto. He received the Fields Medal for breakthroughs that expanded the use of o-minimal methods in arithmetic and complex geometry, including work behind proofs of the André–Oort and Griffiths conjectures.
His shift follows growing engagement with AI: in 2025 he co-authored a paper classifying catastrophic-risk scenarios, and in 2026 he helped verify and explain an OpenAI model's counterexample to a long-standing geometry conjecture.