## PIASECKI Tomasz

Date:
Lun, 29/05/2017 - Ven, 02/06/2017
Site:
Nom:
PIASECKI
Prénom:
Tomasz
Origine:
Université de Varsovie
Origine:
Pologne
Thème:
Analyse des EDP
Invitant:
DANCHIN Raphaël

## Quantifications du tore et transformée de Bargmann.

Type:
Site:
Date:
15/06/2017 - 13:45 - 14:45
Salle:
P2 - P12
Orateur:
ROUBY Ophélie
Localisation:
Université de Lisbonne
Localisation:
Portugal
Résumé:

On s'intéresse aux différentes quantifications du tore de dimension un et plus précisément à la quantification de Berezin-Toeplitz, à la quantification de Weyl et à la quantification de Weyl complexe, notion que nous allons définir comme une variante de la quantification de Weyl complexe de R^2 introduite par Johannes Sjöstrand. Le but de cet exposé est d'établir un lien entre ces différentes quantifications du tore notamment grâce à la transformée de Bargmann.

## Global existence, blowup and scattering for large data supercritical and other wave equations

Type:
Site:
Date:
29/05/2017 - 15:15 - 16:15
Salle:
P1 011
Orateur:
SOFFER Avy
Localisation:
Université Rutgers
Localisation:
États-Unis

## Global existence, blowup and scattering for large data supercritical and other wave equations

Type:
Site:
Date:
29/05/2017 - 14:00 - 15:00
Salle:
P1 011
Orateur:
SOFFER Avy
Localisation:
Université Rutgers
Localisation:
États-Unis

## TALHOUK Raafat

Date:
Lun, 15/05/2017 - Jeu, 18/05/2017
Site:
Nom:
TALHOUK
Prénom:
Raafat
Origine:
Université libanaise
Origine:
Liban
Thème:
Analyse des EDP
Invitant:
GUILLOPÉ Colette

## SOFFER Avy

Date:
Mar, 09/05/2017 - Ven, 09/06/2017
Site:
Nom:
SOFFER
Prénom:
Avy
Origine:
Université Rutgers
Origine:
États-Unis
Thème:
Analyse des EDP
Invitant:
PERELMAN Galina

## Linear systems appear during simulating physical phenomena and optimisation problems

Type:
Site:
Date:
24/05/2017 - 14:00 - 15:00
Salle:
P1-018
Orateur:
AL DAAS Hussam
Localisation:
Université Paris 6
Localisation:
France
Résumé:

In this presentation we will see a general background over iterative linear solvers and the bottlenecks prohibiting reducing the approximately 80 % of simulation time. This time is passed only to solve linear systems. These methods are widely used in both scientific and industrial fields. Parallelising these methods such that they are applied on supercomputers is natural since they rely on a matrix vector product and vector dot product. However, these operations are constrained by the communication time between processors. We will see a brief introduction to HPC. And finally, we will see how we could reduce the global communication by proposing multiple search directions variants.

## Quasi-isometries harmoniques

Site:
Date:
29/05/2017 - 15:00 - 16:00
Salle:
P2 131
Orateur:
BENOIST Yves
Localisation:
Université Paris 11
Localisation:
France
Résumé:

Nous verrons que toute application quasi-isométrique entre variétés de Hadamard pincées est à distance bornée d'une unique application harmonique.

## Surface groups acting on the interval

Site:
Date:
29/05/2017 - 13:45 - 14:45
Salle:
P2 131
Orateur:
SOUTO Juan
Localisation:
Université Rennes 1
Localisation:
France
Résumé:

In this talk I will discuss how to construct surface groups acting by diffeomorphisms on the closed interval. This is a joint work with Ludovic Marquis.

## The moduli space of $2$-convex embedded spheres and tori

Site:
Date:
29/05/2017 - 11:00 - 12:00
Salle:
P2 131
Orateur:
BUZANO Reto
Localisation:
Université de Londres
Localisation:
Royaume-Uni
Résumé:

It is interesting to study the topology of the space of smoothly embedded n-spheres in $\mathbb R^{n+1}$. By Smale’s theorem, this space is contractible for $n=1$ and by Hatcher’s proof of the Smale conjecture, it is also contractible for $n=2$. These results are of great importance, generalising in particular the Schoenflies theorem and Cerf’s theorem. In this talk, I will explain how mean curvature flow with surgery can be used to study a higher-dimensional variant of these results, proving in particular that the space of two-convex embedded spheres is path-connected in every dimension $n$. We then also look at the space of two-convex embedded tori where the question is more intriguing and the result in particular depends on the dimension $n$. This is all joint work with Robert Haslhofer and Or Hershkovits.