Ana Caraiani’s work is characterized by a combination of novel ideas and a fearlessness in the face of technical obstacles that would daunt almost any other researcher. This has enabled her to prove several fundamental theorems in the Langlands program. In the joint paper with Peter Scholze, director of the Max Plack Institute for Mathematics in Bonn, titled “On the generic part of the cohomology of non-compact unitary Shimura varieties” (Annals of Math., 2024), Caraiani proved very general results about the torsion cohomology classes in non-compact Shimura varieties, strengthening the early results in their 2017 paper in the compact case. The proof is a tour de force, combining perfectoid spaces, a mastery of the trace formula, and a new theory of perverse sheaves in p-adic geometry. These results are of intrinsic interest (for example, they give the first indications of a characteristic p version of Arthur’s conjectures), but they also have many applications throughout the Langlands program. One spectacular application of these results is in her joint paper, “Potential automorphy over CM fields” (with Allen, Calegari, Gee, Helm, Le Hung, Newton, Scholze, Taylor, and Thorne, Annals of Math., 2023), which among other results proves the Ramanujan conjecture for Bianchi modular forms, a problem that had been thought of as being completely out of reach.

The Ramanujan conjecture is of analytic nature, asserting a bound on the eigenvalue of a certain differential operator, but the only way in which cases of it have been proved is via algebraic geometry. In particular, the original Ramanujan conjecture for modular forms was proved by Deligne in the 1970s, as a consequence of his proof of the Weil conjectures. However, in the case of Bianchi modular forms there is no direct relationship with algebraic geometry, and it seems to be impossible to make any direct deductions from the Weil conjectures. Langlands (also in the 1970s) suggested a strategy for proving the Ramanujan conjecture as a consequence of his functoriality conjecture. Ana Caraiani and her coauthors’ proof of the Ramanujan conjecture for Bianchi modular forms proceeds via a variant of Langlands’ strategy, and in particular does not use the Weil conjectures.

Most recently with James Newton, in the paper “On the modularity of elliptic curves over imaginary quadratic fields” (arXiv: 2301.10509), Ana Caraiani has improved upon these results and applied them to the modularity of elliptic curves over imaginary quadratic fields. They come close to completely solving it, with only a small number of exceptions (which constitute 0% of cases).

(cited from the news article of the American Mathematical Society, with a few changes)

### About the Ruth Lyttle Satter Prize in Mathematics

Awarded every two years, the **Ruth Lyttle Satter Prize in Mathematics** recognizes an outstanding contribution to mathematics research by a woman in the previous six years. The prize was established by Joan Birman in honor of her sister, Ruth. The 2025 prize will be recognized during the 2025 Joint Mathematics Meetings in January in Seattle.

### About Ana Caraiani

**Ana Caraiani** has close ties to Bonn: In 2016 she became a Bonn Junior Fellow. In 2017, she moved to Imperial College London as a Royal Society Research Fellow and Lecturer, and has been associated with us as a Bonn Research Fellow ever since. From 2021, Ana Caraiani has been a full professor at Imperial College London. She was one of the winners of the 2018 Whitehead Prize of the London Mathematical Society. In 2020, she was elected a Fellow of the American Mathematical Society and was awarded the 2020 EMS Prize. In 2022, she accepted a call to a Hausdorff Chair parallel to her position in London, for one year. During that time Ana Caraiani was awarded the New Horizons Prize in Mathematics, and was an invited speaker at the 2022 ICM.