Jacob Tsimerman, a recipient of the 2026 Fields Prize, has decided to start a position at OpenAI, the company that created ChatGPT. The 2026 Fields Prize was announced on the evening of July 23rd at the International Congress of Mathematicians (ICM) in Philadelphia, USA, with four recipients: Yu Deng, John Pardon, Jacob Tsimerman, and Hong Wang. Tsimerman, 38, was born in Russia, moved to Israel as a child, and grew up in Canada. He won two gold medals at the International Mathematical Olympiad before graduating from the University of Toronto in just two years, later earning his PhD from Princeton University. In 2026, he was honored for his contributions in reshaping o-minimality theory and for playing a role in proving several central conjectures. Tsimerman, who previously wrote a paper categorizing AI scenarios that could wipe out humanity, was skeptical about AI but has shifted his focus to AI safety research. While on leave from the University of Toronto to become a researcher at OpenAI, he wants to use the formal language and verification methods of mathematics to advance AI research, assess progress, understand system decisions, and ensure that AI will not lead to the extinction of humanity.