UCSD Number Theory Seminar (Math 209)

Wednesdays 4-5pm PST, APM 7321 and online

We will run a hybrid seminar this quarter, with talks simultaneously streamed over Zoom. The Zoom meeting code is 993 5967 5186; the password is the four-digit number of the meeting room.

Most talks will be preceded by a "pre-talk" meant for graduate students and postdocs, starting at 3:00pm and lasting about 30 minutes (in-person only, in the same room as the seminar). In any case there will be tea and cookies in the department common room (adjacent to the seminar room) at 3:30pm.

Don't forget to register for Math 209 if you are a UCSD graduate student. Continued department financial support for this seminar is contingent on maintaining sufficient enrollment.

The organizers strive to ensure that all participants in this seminar enjoy a welcoming environment, conducive to the free expression and exchange of ideas. In particular, the pre-talks are meant to provide a safe space for junior researchers to ask questions of the speaker. All participants are expected to cooperate with this effort and encouraged to contact the organizers with any concerns.

To subscribe to our weekly seminar announcement, or to join the number theory group's Zulip discussion server for additional announcements, please contact the organizers. (Thanks to Zulip for providing Sponsored Cloud Hosting for this server.)

As of spring 2020, this site is dynamically generated from researchseminars.org, which see for other seminars worldwide (or for this seminar listed in your local timezone).

Spring Quarter 2025

For previous quarters' schedules, click here.


April 2
+pre-talk

Jake Huryn (Ohio State)
Geometric properties of the "tautological" local systems on Shimura varieties

Some Shimura varieties are moduli spaces of Abelian varieties with extra structure. The Tate module of a universal Abelian variety is a natural source of $\ell$-adic local systems on such Shimura varieties. Remarkably, the theory allows one to build these local systems intrinsically from the Shimura variety in an essentially tautological way, and this construction can be carried out in exactly the same way for Shimura varieties whose moduli interpretation remains conjectural. This suggests the following program: Show that these tautological local systems "look as if" they were arising from the cohomology of geometric objects. In this talk, I will describe some recent progress. It is based on joint work with Kiran Kedlaya, Christian Klevdal, and Stefan Patrikis, as well as joint work with Yifei Zhang.

April 30, 3:00PM, APM 6402

Kristin Lauter (Meta)
Using machine learning to solve hard math problems in practice (AWM colloquium)

AI is taking off and we could say we are living in “the AI Era”. Progress in AI today is based on mathematics and statistics under the covers of machine learning models. This talk will explain recent work on AI4Crypto, where we train AI models to attack Post Quantum Cryptography (PQC) schemes based on lattices. I will use this work as a case study in training ML models to solve hard math problems in practice. Our AI4Crypto project has developed AI models capable of recovering secrets in post-quantum cryptosystems (PQC). The standardized PQC systems were designed to be secure against a quantum computer, but are not necessarily safe against advanced AI! Understanding the concrete security of these standardized PQC schemes is important for the future of e-commerce and internet security. So instead of saying that we are living in a “Post-Quantum” era, we should say that we are living in a “Post-AI” era!

May 21
+pre-talk

Joe Kramer-Miller (Lehigh)
On the diagonal and Hadamard grades of hypergeometric functions

Diagonals of multivariate rational functions are an important class of functions arising in number theory, algebraic geometry, combinatorics, and physics. For instance, many hypergeometric functions are diagonals as well as the generating function for Apery's sequence. A natural question is to determine the diagonal grade of a function, i.e., the minimum number of variables one needs to express a given function as a diagonal. The diagonal grade gives the ring of diagonals a filtration. In this talk we study the notion of diagonal grade and the related notion of Hadamard grade (writing functions as the Hadamard product of algebraic functions), resolving questions of Allouche-Mendes France, Melczer, and proving half of a conjecture recently posed by a group of physicists. This work is joint with Andrew Harder.