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==