Uploaded March 2026 | Updated September 2026, 3 weeks ago
Workshop on Recent Developments in Hodge Theory and O-minimality
4:00pm|Simonyi Hall 101
Topic: (Quasi)-Periods Functions and Derivatives of Period Maps
Speaker: Jacob Tsimerman
Affiliation: Institute for Advanced Study
Date: March 11, 2026
Given a family X→S, one may consider the corresponding fiber-wise (quasi-) period integrals as (multi)-functions on S. Built out of these using a flag variety, one obtains variation of (mixed) hodge structures giving period map S→D/Γ. We study the question of whether one can recover the periods themselves using the period maps by taking derivatives. Specifically, we show that this is usually true (up to an algebraic closure) and explain when it fails. The proofs make use of o-minimality results. Joint work with Bakker and Pila.
Workshop on Recent Developments in Hodge Theory and O-minimality
4:00pm|Simonyi Hall 101
Topic: (Quasi)-Periods Functions and Derivatives of Period Maps
Speaker: Jacob Tsimerman
Affiliation: Institute for Advanced Study
Date: March 11, 2026
Given a family X→S, one may consider the corresponding fiber-wise (quasi-) period integrals as (multi)-functions on S. Built out of these using a flag variety, one obtains variation of (mixed) hodge structures giving period map S→D/Γ. We study the question of whether one can recover the periods themselves using the period maps by taking derivatives. Specifically, we show that this is usually true (up to an algebraic closure) and explain when it fails. The proofs make use of o-minimality results. Joint work with Bakker and Pila.


![Singularities in Mixed Characteristic - Linquan Ma
Members Colloquium
Topic: Singularities in Mixed Characteristic
Speaker: Linquan Ma
Affiliation: Institute for Advanced Study
Date: March 23, 2026 1:30pm
Simonyi 101 and Remote Access
Singularities are local properties of algebraic varieties. For example, the solution set of a polynomial in several variables such as y2=x3
has a singularity at the origin (0,0)
. In algebra, one often studies singularities through the quotient ring, such as C[x,y]/y2−x3
for this example. In this talk, we will give an introduction to recent progress in the study of singularities in mixed characteristic, roughly speaking, these correspond to quotients of Z[x1,...,xn]
by polynomials with integer coefficients. A central theme in this study is the use of so-called big Cohen-Macaulay algebras, these are often large (non-Noetherian) rings that nevertheless enjoys remarkably nice homological properties (and whose existence is related to recent developments in p-adic Hodge theory). We also discuss some applications of the mixed characteristic singularity theory to questions in birational geometry. Singularities in Mixed Characteristic - Linquan Ma](https://i.ytimg.com/vi/gTOsV2vXFz8/mqdefault.jpg)

![An Average-Degree Bound for Hamming Hypergraphs, with Applications to Optimal PAC...- Nataly Brukhim
Computer Science/Discrete Mathematics Seminar II
10:30am|Simonyi 101 and Remote Access
Topic: An Average-Degree Bound for Hamming Hypergraphs, with Applications to Optimal PAC Learning
Speaker: Nataly Brukhim
Affiliation: Institute for Advanced Study
Date: May 26, 2026
I will describe recent breakthrough results in multiclass PAC learning that characterize the optimal sample complexity. The talk will discuss recent work of Chirag Pabbaraju, as well as work of Steve Hanneke, Qinglin Meng, Shay Moran, and Amirreza Shaeiri.
Determining the optimal sample complexity reduces to a structural question about the Hamming-graph representation of the hypothesis class. These are hypergraphs whose vertices lie in [k]^n, where each set of vertices that agree on all coordinates except one forms an edge. It has been shown that bounding the average degree of these hypergraphs yields bounds on the sample complexity of learning. A long-standing conjecture was that this average degree can be controlled by the Daniely–Shalev-Shwartz dimension, a combinatorial dimension introduced in 2014.
The DS dimension is a natural generalization of the VC dimension, and was shown to bound the sample complexity of multiclass PAC learning in joint work with Carmon, Dinur, Moran, and Yehudayoff (2022). However, the correct dependence on the dimension remained open, with a polynomial gap between the upper and lower bounds. The recent work of Pabbaraju closes this gap by resolving the average-degree conjecture. The proof is based on a simple linear-algebraic method, which I will describe in the talk. An Average-Degree Bound for Hamming Hypergraphs, with Applications to Optimal PAC...- Nataly Brukhim](https://i.ytimg.com/vi/g_wp-OhFxeU/mqdefault.jpg)





