Seminars Sorted by Series

Seminar in Analysis and Geometry

Feb
01
2022

Seminar in Analysis and Geometry

Euler flows with local energy dissipation
2:00pm|Simonyi Hall 101 and Remote Access

The incompressible 3D Euler equations have total kinetic energy conservation for smooth (spatially periodic) solutions. In the recent resolution of the Onsager conjecture by Isett, on the other hand, below certain threshold Hölder regularity, Euler...

Feb
08
2022

Seminar in Analysis and Geometry

Totally nonparallel immersions
2:00pm|Simonyi Hall 101 and Remote Access

An immersion from a smooth n-dimensional manifold $M$ into $R^q$ is called totally nonparallel if, for every pair of distinct points $x$ and $y$ in $M$, the tangent spaces at $f(x)$ and $f(y)$ contain no parallel lines. The simplest example is the...

Feb
15
2022

Seminar in Analysis and Geometry

$H^{1/2-}$ weak solutions of the 3D Euler equations
2:00pm|Simonyi Hall 101 and Remote Access

In this talk, I will discuss joint work with Tristan Buckmaster, Nader Masmoudi, and Vlad Vicol in which we construct non-conservative solutions to the Euler equations which belong to the regularity class $C^0_t H^{1/2-}_x$. The motivation for such...

Feb
22
2022

Seminar in Analysis and Geometry

On the Lagrangian cobordism relation on Legendrian links
2:00pm|Simonyi Hall 101 and Remote Access

Lagrangian cobordism induces a preorder on the set of Legendrian links in any contact 3-manifold. We show that any finite collection of null-homologous Legendrian links in a tight contact 3-manifold with a common rotation number has an upper bound...

Mar
01
2022

Seminar in Analysis and Geometry

Weak solutions to MHD equations
2:00pm|Simonyi Hall 101 and Remote Access

The talk will be devoted to explain how to construct weak solutions to 3D Ideal MHD equations obtained by convex integration (in the non smooth regime). We will show the existence of bounded weak solutions dissipating energy and cross helicity but...

Mar
22
2022

Seminar in Analysis and Geometry

Level Sets of Weakly Lipschitz Functions
2:00pm|Simonyi Hall 101 and Remote Access

We will discuss the regularity properties and size of generic level sets of functions that satisfy weak local Lipschitz conditions.

Apr
19
2022

Seminar in Analysis and Geometry

Singularity formation for reduced models of fluid equations
2:00pm|Simonyi Hall 101 and Remote Access

The non-resistive electron magnetohydrodynamics (MHD) has some peculiar connection with the Euler equation. Some one-dimensional reduced models are suggested as an attempt to build intuition toward understanding the nonlinear structure and dynamics...

Apr
26
2022

Seminar in Analysis and Geometry

Global well-posedness for the 2D one-phase Muskat problem
2:00pm|Simonyi Hall 101 and Remote Access

I will present a recent result jointly with Francisco Gancedo (Universidad de Sevilla) and Huy Q. Nguyen (University of Maryland), in which we obtained the global well-posedness for the 2D one-phase Muskat problem with arbitrary large Lipschitz...

May
03
2022

Seminar in Analysis and Geometry

Metrics of constant Chern scalar curvature
Xi Sisi Shen
2:00pm|Simonyi Hall 101 and Remote Access

We discuss the existence problem of constant Chern scalar curvature metrics on a compact complex manifold. We prove a priori estimates for these metrics conditional on an upper bound on the entropy, extending a recent result by Chen-Cheng in the...

May
10
2022

Seminar in Analysis and Geometry

Remarks on the long-time dynamics of 2D Euler
2:00pm|Simonyi Hall 101 and Remote Access

We will discuss some old and new results concerning the long-time behavior of solutions to the two-dimensional incompressible Euler equations.  Specifically, we discuss whether steady states can be isolated, wandering for solutions starting nearby...

Seminar in Analysis and Geometry (cancelled)

Seminar on Global Analysis

Nov
15
2022

Seminar on Global Analysis

Index Theory for Lorentzian Manifolds
Christian Bär
4:30pm|Simonyi 101 and Remote Access

Index theory goes back to Atiyah and Singer and deals with elliptic operators on Riemannian manifolds. It has numerous applications in geometry, topology, mathematical physics and other fields. On a Lorentzian manifold, naturally associated...

Shimura Varieties and Trace Formula Seminar

Oct
03
2008

Shimura Varieties and Trace Formula Seminar

On the Truncated Hitchin Fibration and the Weighted Fundamental Lemma (joint work with G\'erard Laumon)
P.-H. Chaudouard
10:30am|West Bldg. Lecture Hall

The fundamental lemma of Langlands and Shelstad is a family of combinatorial identities between local orbital integrals. It is necessary to the stabilization of the elliptic part of the Arthur-Selberg trace formula. In order to stabilize the whole...

Oct
03
2008

Shimura Varieties and Trace Formula Seminar

On the Cohomology of Non-Compact Unitary Shimura Varieties
S. Morel
2:00pm|West Bldg. Lecture Hall

In this talk, I will explain how the method originally developed by Ihara, Langlands and Kottwitz to compute the cohomology of a Shimura variety (use the Grothendieck-Lefschetz fixed point formula in positive characteristic to calculate the trace on...

Oct
13
2008

Shimura Varieties and Trace Formula Seminar

On the Truncated Hitchin Fibration and the Weighted Fundamental Lemma (joint work with G\'erard Laumon)
P.-H. Chaudouard
10:30am|West Bldg. Lecture Hall

The fundamental lemma of Langlands and Shelstad is a family of combinatorial identities between local orbital integrals. It is necessary to the stabilization of the elliptic part of the Arthur-Selberg trace formula. In order to stabilize the whole...

Oct
13
2008

Shimura Varieties and Trace Formula Seminar

On the Cohomology of Non-Compact Unitary Shimura Varieties
S. Morel
2:00pm|S-101

In this talk, I will explain how the method originally developed by Ihara, Langlands and Kottwitz to compute the cohomology of a Shimura variety (use the Grothendieck-Lefschetz fixed point formula in positive characteristic to calculate the trace on...

Oct
24
2008

Shimura Varieties and Trace Formula Seminar

Construction of Galois Representations
2:00pm|S-101

We report a recent result, due to Clozel-Harris-Labesse, Morel and the speaker, on the previous work of Clozel, Kottwitz, Harris-Taylor and Taylor-Yoshida. There are two main features in our work. One feature, which is also crucial in the other...

Oct
31
2008

Shimura Varieties and Trace Formula Seminar

Construction of Galois Representations
10:30am|S-101

We report a recent result, due to Clozel-Harris-Labesse, Morel and the speaker, on the previous work of Clozel, Kottwitz, Harris-Taylor and Taylor-Yoshida. There are two main features in our work. One feature, which is also crucial in the other...

Oct
31
2008

Shimura Varieties and Trace Formula Seminar

Arithmetic Compactifications of PEL-Type Shimura Varieties
2:00pm|S-101

In this lecture, we will try to explain the essential ingredients in the construction of toroidal and minimal compactifications of smooth integral models of (general) PEL-type Shimura varieties, following the approaches of Faltings and Chai. Since...

Nov
03
2008

Shimura Varieties and Trace Formula Seminar

Arithmetic Compactifications of PEL-Type Shimura Varieties
3:30pm|S-101

In this lecture, we will try to explain the essential ingredients in the construction of toroidal and minimal compactifications of smooth integral models of (general) PEL-type Shimura varieties, following the approaches of Faltings and Chai. Since...

Nov
14
2008

Shimura Varieties and Trace Formula Seminar

A Global Analogue of Springer Representations
Z.-W. Yun
10:30am|S-101

I propose an analogue of Springer representations when the finite field in the classical version is replaced by a global function field. The Grothendieck-Springer alternation will be replaced by the so-called parabolic Hitchin fibration. I will...

Nov
14
2008

Shimura Varieties and Trace Formula Seminar

Twisted Relative Trace Formulae with a View Towards Unitary Groups I and II
2:00pm|S-101

We will introduce the twisted relative trace formula and prove a relative fundamental lemma in this setting using an analogue of Kottwitz's argument in the base change situation. Applications to the study of distinction on unitary groups will be...

Nov
21
2008

Shimura Varieties and Trace Formula Seminar

Twisted Relative Trace Formulae with a View Towards Unitary Groups I and II
10:30am|S-101

We will introduce the twisted relative trace formula and prove a relative fundamental lemma in this setting using an analogue of Kottwitz's argument in the base change situation. Applications to the study of distinction on unitary groups will be...

Nov
21
2008

Shimura Varieties and Trace Formula Seminar

Reduction Theory for p-Adic Moduli Spaces of Abelian Varieties and p-Divisible Groups
L. Fargues
2:00pm|S-101

I will first explain one can parametrize some particular cases of p-adic moduli spaces of p-divisible groups, Lubin-Tate spaces, by the geometric realization of Bruhat-Tits buildings. By a p-adic space I mean Berkovich analytic space. I will then...

Dec
05
2008

Shimura Varieties and Trace Formula Seminar

Formal Degrees and Adjoint Gamma Factors
10:30am|S-101

Harish-Chandra established the Plancherel formula for reductive groups over local fields, in which formal degrees and Plancherel measures are key ingredients. In this talk, we give a natural extension of Langlands' conjecture, which relates...

Dec
05
2008

Shimura Varieties and Trace Formula Seminar

On the Cohomology of Some Non-Compact Shimura Varieties III: Applications
2:00pm|S-101

In this talk, I will at long last give applications of the previous two technical talks. First I will give some direct (and imperfect) applications to representations of the unitary or symplectic groups themselves. Then I will present some...

Short Talks by Postdoctoral Members