Vesselin Dimitrov

Vesselin Atanasov Dimitrov is a Bulgarian mathematician. He is a professor at Caltech.
The body of his work includes notable contributions to arithmetic geometry, Diophantine geometry, theory of modular forms and number theory.
Dimitrov received the Oberwolfach Prize in 2022. In 2025, he received the Frank Nelson Cole Prize, the Salem Prize, and the Fermat Prize.

Research in mathematics

In 2019 Dimitrov proved the Schinzel–Zassenhaus conjecture on algebraic units that are not roots of unity.
Together with Ziyang Gao and Philipp Habegger he authored "Uniformity in Mordell-Lang for curves". In this paper they obtain a uniform version of the Mordell conjecture.
In collaboration with Frank Calegari and Yunqing Tang, Dimitrov proved the unbounded denominators conjecture of A.O.L. Atkin and Swinnerton-Dyer: if a modular form is not modular for some congruence subgroup of the modular group, then the Fourier coefficients of have unbounded denominators.

In 2005 he won a silver medal in the International Mathematics Olympiad, representing Bulgaria.
He earned a PhD from Yale University in 2017 under the supervision of Alexander Goncharov. His thesis is titled "Diophantine approximations by special points and applications to Dynamics and Geometry".

Dimitrov's work has been recognized by the following awards:

In 2022 he was awarded the David Goss Prize in Number Theory and the Oberwolfach Prize
In 2023 he was awarded IMI Mathematics Prize
In 2025 he was awarded the Salem Prize "for fundamental contributions to Diophantine geometry and number theory".
In October 2025, he was named a recipient of the 2026 Frank Nelson Cole Prize in Number Theory, jointly with Frank Calegari and Yunqing Tang, for their paper "The unbounded denominators conjecture",.
2025: Fermat Prize.