Previous Conferences & Workshops

Dec
11
2020

Workshop on Turbulence

Turbulence as Gibbs Statistics of Vortex Sheets
Alexander Migdal
3:30pm|Virtual Event via Zoom

Abstract: We study the vortex sheet solutions of the Euler equation, which correspond to the tangent discontinuity of the velocity field.

We observe that stationary flows correspond to the Hamiltonian's minimization by the tangent discontinuity...

Dec
11
2020

Workshop on Turbulence

Fluid Turbulence, Thermal Noise and Spontaneous Stochasticity
Gregory Eyink
2:30pm|Virtual Event via Zoom

Abstract: I will explain that incompressible Navier-Stokes is the wrong equation to describe turbulence in low Mach number molecular fluids because it neglects the effects of thermal noise. There should, in fact, be strong effects of thermal noise...

Dec
11
2020

Workshop on Turbulence

Status of experiments and simulations on scaling problems in turbulence
1:30pm|Virtual Event via Zoom

Abstract: We present an elementary summary of known results, and open questions, on scaling problems in hydrodynamic turbulence in three dimensions. The goal is to provide some background for the two talks to follow, and summarize Victor Yakhot's...

Dec
10
2020

Joint IAS/Princeton University Number Theory Seminar

On the Liouville function at polynomial arguments
Joni Teräväinen
4:30pm|Remote Access

Let $\lambda$ be the Liouville function and $P(x)$ any polynomial that is not a square. An open problem formulated by Chowla and others asks to show that the sequence $\lambda(P(n))$ changes sign infinitely often. We present a solution to this...

Dec
09
2020

Mathematical Conversations

Determinants, hyperbolicity, and interlacing
5:30pm|Remote Access

Hyperbolic polynomials are a multivariate generalization of real-rooted polynomials that originated in the study of partial differential equations and have since found applications in many other fields, including operator theory, optimization, and...

Dec
09
2020

Geometric and Modular Representation Theory Seminar

Lefschetz operators, Hodge-Riemann forms, and representations
3:00pm|Simonyi Hall 101 and Remote Access

Motivated by a formal similarity between the Hard Lefschetz theorem and the geometric Satake equivalence we study vector spaces that are graded by a weight lattice and are endowed with linear operators in simple root directions. We allow field...

Dec
09
2020

Stability and Testability

Vanishing of cohomology for groups acting on buildings
Izhar Oppenheim
11:00am|Remote Access

In his seminal paper from 1973, Garland introduced a machinery for proving vanishing of group cohomology for groups acting on Bruhat-Tits buildings. This machinery, known today as “Garland’s method”, had several applications as a tool for proving...