Holomorphic isometries from the Poincare disc into bounded symmetric domains

Speaker: 

Yuan Yuan

Institution: 

Syracuse University

Time: 

Tuesday, September 26, 2017 - 4:00pm to 5:00pm

Location: 

RH 306

I will first overview the classical holomorphic isometry problem between complex manifolds, in particular between bounded symmetric domains. When the source is the unit ball, in general the characterization of holomorphic isometries to bounded symmetric domains is not quite clear. With Shan Tai Chan, we recently characterized the holomorphic isometries from the Poincare disc to the product of the unit disc with the unit ball and it  provided new examples of holomorphic isometries from the Poincare disc into irreducible bounded symmetric domains of rank at least 2.

 

 

On closedness of ALE SFK metrics on minimal ALE Kahler surfaces

Speaker: 

Jiyuan Han

Institution: 

University of Wisconsin, Madison

Time: 

Tuesday, September 19, 2017 - 4:00pm to 5:00pm

Host: 

Location: 

RH 306

Under some topological assumption (which gives the boundedness of Sobolev constant), we construct the space of ALE SFK metrics on minimal ALE Kahler surfaces asymptotic to C^2/G, where G is a finite subgroup of U(2). This is a joint work with Jeff Viaclovsky.

 

From Barbilian Geometries to Gromov Hyperbolic Spaces

Speaker: 

Bogdan Suceava

Institution: 

Cal State, Fullerton

Time: 

Tuesday, October 17, 2017 - 4:00pm to 5:00pm

Host: 

Location: 

RH 306

In 1934, Wilhelm Blaschke’s attention focused on a recent construction in metric geometry proposed by Dan Barbilian as a generalization of various models of hyperbolic geometry. It was the year when S.-S. Chern started his doctoral program under Blaschke’s supervision in Hamburg and when in several academic centers in Europe scholars were interested in generalizations of Riemannian geometry. Introduced originally in 1934, Barbilian’s metrization procedure induces a distance on a planar domain through a metric formula given by the so-called logarithmic oscillation. In 1959, Barbilian generalized this process to more general domains. In our discussion we plan to show that these spaces are naturally related to Gromov hyperbolic spaces. In several works written with W.G. Boskoff, we explore this connection. We conclude our talk by stating several open problems related to this content.

Isometric embeddings via heat kernel

Speaker: 

Ke Zhu

Institution: 

Minnesota State University

Time: 

Monday, June 5, 2017 - 4:00pm

Location: 

RH 340N

The Nash embedding theorem states that every Riemannian
manifold can be isometrically embedded into some Euclidean space with
dimension bound. Isometric means preserving the length of every
path. Nash's proof involves sophisticated perturbations of the
initial embedding, so not much is known about the geometry of the
resulted embedding.
     In this talk, using the eigenfunctions of the Laplacian
operator, we construct canonical isometric embeddings of compact
Riemannian manifolds into Euclidean spaces, and study the geometry of
embedded images. They turn out to have large mean curvature
(intuitively, very bumpy), but the extent of oscillation is about the
same at every point. More can be said about global quantities like
the center of mass. This is a joint work with Xiaowei Wang.

Equivariant eta forms and differential K theory

Speaker: 

Bo Liu

Institution: 

UC Santa Barbara

Time: 

Tuesday, June 6, 2017 - 4:00pm to 5:00pm

Location: 

RH 306

The eta form of Bismut–Cheeger is the higher degree version of the Atiyah-Patodi-Singer eta invariant, i.e. it is exactly the boundary correction term in the family index theorem for manifolds with boundary. In this talk, I'll study the properties of eta forms and extend them to the equivariant version for compact Lie group action. Moreover, the applications of eta forms in differential K theory will be discussed.

Free boundary minimal hypersurfaces

Speaker: 

Lucas Ambrozio

Institution: 

University of Chicago

Time: 

Tuesday, June 13, 2017 - 4:00pm to 5:00pm

Location: 

RH 340P

We will review some recent work on free boundary minimal
hypersurfaces. In particular, we will explain a geometric classification
of the critical catenoid (joint with Ivaldo Nunes) and discuss what
information about such hypersurfaces in a general ambient manifold one can
extract from the knowledge of their Morse index (joint with Alessandro
Carlotto and Ben Sharp).

Connecting the Kontsevich-Witten and Hodge tau-functions by the Virasoro operators

Speaker: 

Xiaobo Liu

Institution: 

Peking Univ. and Notre Dame University

Time: 

Tuesday, May 2, 2017 - 4:00pm to 5:00pm

Location: 

RH 306

Kontsevich-Witten tau-function and the Hodge tau-function
are generating functions for two types of intersection numbers on
moduli spaces of stable curves. Both of them are tau functions for the
KP hierarchy. In this talk, I will describe how to connect these two
tau-functions by differential operators belonging to the
$\widehat{GL(\infty)}$ group. Indeed, these two tau-functions can be
connected using Virasoro operators. This proves a conjecture posted by
Alexandrov. This is a joint work with Gehao Wang.

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