Cristian Dumitru Popescu

Cristian Dumitru Popescu (born 1964) is a Romanian-American mathematician at the University of California, San Diego. His research interests are in algebraic number theory, and in particular, in special values of L-functions.

Education and career
The son of historian Dumitru Micu Popescu and biologist Rodica Jerișteanu, Popescu was born in 1964 in Novaci, Gorj County. After completing his undergraduate studies at the Faculty of Mathematics of the University of Bucharest, he obtained his Ph.D. from the Ohio State University in 1996, with thesis "On a refined Stark conjecture for function fields" written under the direction of Karl Rubin. He became a professor at Johns Hopkins University, after which he moved to his current position as a professor at UC San Diego.

Research contributions
Popescu formulated and proved function field versions of the Gras conjectures and Rubin's integral refinement of the abelian Stark conjectures. He has also made important contributions to the Stark conjectures over number fields, formulating an alternative to Rubin's refinement, known as Popescu's conjecture. Although slightly weaker than Rubin's conjecture, it has the advantage that it can presently be shown to remain true under raising the base field or lowering the top field of the extension. Popescu and Cornelius Greither formulated equivariant versions of Iwasawa's main conjecture over function fields and number fields, proving unconditionally the function field version and conditionally the number field version. These conjectures have important implications for the Brumer–Stark conjecture, the Coates-Sinnott conjecture and Gross' conjecture on special values of L-functions.

Recognition
Popescu was awarded the Simion Stoilow Prize by the Romanian Academy in 2002. In 2015-2016, he was a Simons Fellow at Harvard University. He was elected to the 2021 class of fellows of the American Mathematical Society "for contributions to number theory and arithmetic geometry". He is an honorary member of the Institute of Mathematics of the Romanian Academy.