Previous Conferences & Workshops

Sep
22
2025

Members' Colloquium

Unlikely Intersections and Connections to Geometry
1:30pm|Wolfensohn Hall and Remote Access

The field of unlikely Intersections presents a robust paradigm for problems in which several subjects intermingle: arithmetic, o-minimality, and hodge theory. The goal of this talk will be to introduce some of those connections. My aim is to...

Sep
22
2025

Computer Science/Discrete Mathematics Seminar I

Balancing Extensions in Posets of Large Width
Maxwell Aires
11:00am|Rubenstein Commons | Meeting Room 5

Abstract: A linear extension of $P$ is a linear ordering compatible with the poset relations. Let $p(x< y), p(y < x))$ and $\delta(P)$ be the maximum value of $\delta(x, y)$ over all $x, y$ in $P$. The following two conjectures about $\delta(P)$ are both well-known:

  1. (The "1/3-2/3 Conjecture") $\delta(P) \geq \frac{1}{3}$ whenever $P$ is not a chain.
  2. (The "Kahn-Saks Conjecture") $\delta(P) \to \frac{1}{2}$ as $w(P) \to \infty$ (where $w(P)$ is the maximum size of an antichain in $P$).

While still far from either of these, we prove a number of conditions for $\delta(P) \to \frac{1}{2}$ and $\delta(P) \geq \frac{1}{e} - o(1)$, using a mix of geometric and probabilistic techniques. Joint with Jeff Kahn.

Sep
18
2025

Joint PU/IAS Number Theory

A P-Adic Extension Theorem for Shimura Varieties and Period Images
3:30pm|Fine 110, Princeton University

Borel proved that every holomorphic map from a product of punctured unit discs to a complex Shimura variety extends to a map from a product of discs to its Bailey-Borel compactification. In joint work with Oswal, Zhu, and Patel, we proved a p-adic...

Sep
16
2025

Joint IAS/PU Groups and Dynamics Seminar

Orthogonality of Sequences, Characteristic Classes in Ergodic Theory and the Local Fourier Uniformity Problem for Small Sets
Mariusz Lemanczyk
4:30pm|314 Fine Hall

Given a bounded sequence of zero mean, we study the problem of its orthogonality to all continuous  observables in topological dynamical systems whose all invariant measures yield measure-theoretic systems belonging to a fixed characteristic class...

Sep
15
2025

Joint IAS/PU Arithmetic Geometry

A New Geometric Approach to $p$-adic Differential Equations
Guido Bosco
3:30pm|Princeton University, Fine Hall 224

In the past decade, $p$-adic Hodge theory has been transformed by the discovery of perfectoid spaces and the Fargues–Fontaine curve. One area, however, that has remained almost untouched by these breakthroughs is the theory of $p$-adic differential...

Sep
15
2025

Computer Science/Discrete Mathematics Seminar I

Combinatorial and Geometric Challenges in PAC Learning with Partial Concepts
Shay Moran
11:00am|Simonyi Hall 101 and Remote Access

I will describe a recent extension of the classical PAC (Probably Approximately Correct) learning framework [Vapnik and Chervonenkis, 1970s; Valiant, 1980s]. This extension makes it possible to model a wide range of common and practical data...

Sep
08
2025

Joint IAS/PU Arithmetic Geometry

The Gysin Map in 𝐏¹-homotopy Theory
Longke Tang
3:30pm|Princeton University, Fine Hall 224

The Gysin map, or the wrong-way map, is a classical construction that has been available for various cohomology theories and in 𝐀¹-homotopy theory. In this talk, I will give a construction of it based on 𝐏¹-homotopy theory, so that it specializes to...

Jun
20
2025

IAS/Princeton/Montreal/Paris/Tel-Aviv Symplectic Geometry Zoominar

A toric case of the Thomas-Yau conjecture
Jacopo Stoppa
9:15am|Remote Access

We consider a class of Lagrangian sections L contained in certain Calabi-Yau Lagrangian fibrations (mirrors of toric weak Fano manifolds). We prove that a form of the Thomas-Yau conjecture holds in this case: L is Hamiltonian isotopic to a special...

Jun
17
2025

Computer Science/Discrete Mathematics Seminar II

Upper Bounds for Multicolour Ramsey Numbers
Marius Tiba
10:30am|Simonyi Hall 101 and Remote Access

The $r$-colour Ramsey number $R_r(k)$ is the minimum $n \in \mathbb{N}$ such that every $r$-colouring of the edges of the complete graph $K_n$ on $n$ vertices contains a monochromatic copy of $K_k$. We prove, for each fixed $r \ge 2$, that 

$$R_r(k)...