Cristian Dumitru Popescu (born 1964) is a
Romanian-American
Romanian Americans are Americans who have Romanian ancestry. According to the 2017 American Community Survey, 478,278 Americans indicated Romanian as their first or second ancestry, however other sources provide higher estimates, which are most ...
mathematician at the
University of California, San Diego. His research interests are in
algebraic number theory
Algebraic number theory is a branch of number theory that uses the techniques of abstract algebra to study the integers, rational numbers, and their generalizations. Number-theoretic questions are expressed in terms of properties of algebraic ob ...
, and in particular, in
special values of L-functions
In mathematics, the study of special values of L-functions is a subfield of number theory devoted to generalising formulae such as the Leibniz formula for pi, namely
:1 \,-\, \frac \,+\, \frac \,-\, \frac \,+\, \frac \,-\, \cdots \;=\; \frac,\! ...
.
Education and career
The son of historian Dumitru Micu Popescu and biologist Rodica Jerișteanu,
Popescu was born in 1964 in
Novaci,
Gorj County
Gorj County () is a county ( județ) of Romania, in Oltenia, with its capital city at Târgu Jiu. ''Gorj'' comes from the Slavic ''Gor(no)-'' Jiu (“upper Jiu”), in contrast with Dolj (“lower Jiu”).
Demographics
In 2011, the county had a ...
.
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 In number theory, the Stark conjectures, introduced by and later expanded by , give conjectural information about the coefficient of the leading term in the Taylor expansion of an Artin L-function associated with a Galois extension ''K''/''k'' ...
. 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 Brumer–Stark conjecture is a conjecture in algebraic number theory giving a rough generalization of both the analytic class number formula for Dedekind zeta functions, and also of Stickelberger's theorem about the factorization of Gauss sums ...
, the Coates-Sinnott conjecture and
Gross' conjecture on special values of L-functions.
Recognition
Popescu was awarded the
Simion Stoilow Prize The Simion Stoilow Prize ( ro, Premiul Simion Stoilow) is the prize offered by the Romanian Academy for achievements in mathematics. It is named in honor of Simion Stoilow.
The prize is awarded either for a mathematical work or for a cycle of works ...
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.
References
External links
*
Home page
{{DEFAULTSORT:Popescu, Cristian
1964 births
People from Gorj County
Living people
20th-century Romanian mathematicians
20th-century American mathematicians
21st-century Romanian mathematicians
21st-century American mathematicians
Romanian emigrants to the United States
University of Bucharest alumni
Ohio State University alumni
Johns Hopkins University faculty
University of California, San Diego faculty
Number theorists
Fellows of the American Mathematical Society