Université Paris-Est Université Paris-Est - Marne-la-Vallée Université Paris-Est - Créteil Val-de-Marne Centre National de la Recherche Scientifique

IMJ

Institut de Mathématiques de Jussieu

Harmonic morphisms from Lie groups and symmetric spaces

Site: 
Date: 
10/10/2011 - 14:00 - 15:00
Salle: 
0D1
Orateur: 
GUDMUNDSSON Sigmundur
Localisation: 
Université de Lund
Localisation: 
Suède
Résumé: 

It follows from the famous Weierstrass representation, for MINIMAL surfaces in $3$-dimensional Euclidean space, that any such surface can locally be presented by a (weakly) CONFORMAL HARMONIC immersion from the complex plane given in terms of two holomorphic functions.

The inverse image of a regular value of a complex-valued holomorphic function on a Kähler manifold is a MINIMAL submanifold of codimension $2$. It is a direct consequence of the Cauchy-Riemann equations that such a function is a horizontally (weakly) CONFORMAL HARMONIC submersion.

Harmonic morphisms are maps $(M,g)\rightarrow (N,h)$ between Riemannian manifolds generalizing holomorphic functions from Kähler manifolds. If the codomain is the complex plane any regular fibre is a MINIMAL submanifold of $M$ of codimension $2$.

In this talk we will give a brief introduction to the theory of harmonic morphisms and then discuss the existence of complex-valued solutions from Lie groups and symmetric spaces.

The Alexandrov problem in a quotient space of $\mathbb{H}^2 \times \mathbb{R}$

Site: 
Date: 
26/09/2011 - 15:30 - 16:30
Salle: 
0D1
Orateur: 
MENEZES Ana Maria
Localisation: 
IMPA
Localisation: 
Brésil
Résumé: 

In this talk, we will prove an Alexandrov type theorem for a quotient space of $\mathbb{H}^2 \times \mathbb{R}$. More precisely, we will classify the compact embedded surfaces with constant mean curvature in the quotient of $\mathbb{H}^2 \times \mathbb{R}$ by a subgroup of isometries generated by a parabolic translation along horocycles of $\mathbb{H}^2$ and a vertical translation. Moreover, we will construct some examples of periodic minimal surfaces in $\mathbb{H}^2 \times \mathbb{R}$ .

Rigidity of min-max minimal spheres in three-manifolds

Site: 
Date: 
26/09/2011 - 14:00 - 15:00
Salle: 
0D1
Orateur: 
CODA MARQUES Fernando
Localisation: 
IMPA
Localisation: 
Brésil
Résumé: 

In this talk we will consider min-max minimal surfaces in three-manifolds and describe some related scalar curvature rigidity results. We will also mention some sharp estimates for the width in the case of positive Ricci curvature. The proofs use Ricci flow. This is joint work with Andre Neves.

Transformations of surfaces and their applications to spectral theory

Site: 
Date: 
27/06/2011 - 14:00
Salle: 
0D 01
Orateur: 
TAIMANOV Iskander
Localisation: 
Université de Novossibirsk
Localisation: 
Russie

Problème de Cauchy en relativité générale

Site: 
Date: 
20/06/2011 - 14:00
Salle: 
0D 01
Orateur: 
HUMBERT Emmanuel
Localisation: 
Université Nancy 1
Localisation: 
France

Lieu de concentration des surfaces à courbure moyenne constante dans une variété

Site: 
Date: 
06/06/2011 - 14:00
Salle: 
0D 01
Orateur: 
LAURAIN Paul
Localisation: 
ENS Lyon
Localisation: 
France

Espace des modules des anneaux minimaux

Site: 
Date: 
30/05/2011 - 14:00
Salle: 
0D 01
Orateur: 
HAUSWIRTH Laurent

Le problème de Minkowski dans l'espace de Minkowski

Site: 
Date: 
23/05/2011 - 14:00
Salle: 
0D 01
Orateur: 
ZEGHIB Ghani
Localisation: 
ENS Lyon
Localisation: 
France

Inégalités de type Cacioppoli pour les hypersurfaces CMC et applications

Site: 
Date: 
09/05/2011 - 14:00
Salle: 
0D 01
Orateur: 
NELLI Barbara
Localisation: 
Université de l'Aquila
Localisation: 
Italie

Renormalized area, Willmore energy and boundary regularity

Site: 
Date: 
02/05/2011 - 14:00
Salle: 
0D 01
Orateur: 
MAZZEO Rafe
Localisation: 
Université Stanford
Localisation: 
États-Unis
Résumé: 

In previous work with Spyros Alexakis, we considered the renormalized energy of complete properly embedded minimal surfaces in $\mathbb{H}^3$ and proved several structure theorems about it. I will report on that older work as well as our new results showing how control on this renormalized area yields a certain amount of regularity of the asymptotic boundary at infinity.

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