type actualité
actualités

Recrutement Post-doc sur l'ANR RAGE

Date de début de l'actualité
24-02-2021 08:04
Date de fin de l'actualité
25-04-2021 08:04

A post-doc position funded by the ANR RAGE project is open. application informations

Local dynamics of holomorphic maps on normal surface singularities

Matteo Ruggiero
Etablissement de l'orateur
IMJ-PRG, Université de Paris
Date et heure de l'exposé
Lieu de l'exposé
visioconférence
Résumé de l'exposé

To describe the behavior of the iterates of a holomorphic germ f on a complex surface X fixing a (possibly singular) point x0, we are led to study the lifts fπ to birational models Xπ over (X,x0). In general fπ has indeterminacy points: when the fπ-orbits eventually avoid these indeterminacy points, we say that X_π is algebraically stable. In a joint work with William Gignac, we show the existence of algebraically stable models in this setting (but for one class of exceptions, where no such models exist). The proof relies on fixed point theorems for the dynamics induced on suitable valuation spaces, following Favre and Jonsson.

Stability of kinks in one-dimensional Klein-Gordon equations

Pierre Germain
Etablissement de l'orateur
Courant Institute - NY
Date et heure de l'exposé
Lieu de l'exposé
Salles des séminaires ZOOM
Résumé de l'exposé

Kinks are topological solitons, which appear in (nonlinear) one-dimensional Klein-Gordon equations, the Phi-4 and Sine-Gordon equations being the best-known examples. I will present new results which give asymptotic stability for kinks, with an optimal decay rate, in some cases. The proof relies on the distorted Fourier transform associated to the linearized equation around the kink; this method should be of interest for more general soliton stability problems. This is joint work with Fabio Pusateri.

type actualité
Colloque

Conference "Facets of Real Algebraic Geometry" (dedicated to Viatcheslav Kharlamov on the occasion of his 70-th birthday), June 21-25, 2021

Date de début de l'actualité
21-06-2021 10:00
Date de fin de l'actualité
25-06-2021 17:00

The conference is devoted to important progress of real algebraic geometry in the first two decades of the 21st century, as well as to its numerous new interactions with other areas of mathematics. It will be anopportunity to gather together researchers of different cultures around different facets of real algebraic geometry.
The conference will take place in Nantes.

Organizing committee:
Erwan Brugallé, Sergey Finashin, Ilia Itenberg, Jean-Yves Welschinger, Michele Stecconi

Please, send an email to Michele Stecconi (Michele.Stecconi@univ-nantes.fr) if you plan to participate at the school or/and the conference.
The deadline for registration is May 31st.
Information and registration

type actualité
Colloque

Summer school of the ANR "Symplectic, real, and tropical aspects of enumerative geometry", Le Croisic, June 14-18, 2021

Date de début de l'actualité
14-06-2021 10:00
Date de fin de l'actualité
18-06-2021 17:00

The goal of this school is to present several of these aspects through 3 courses of 4 hours each.

The lectures will be given by

  • Pierrick Bousseau (CNRS, Université de Paris Sud)
  • Viatcheslav Kharlamov (Université de Stasbourg)
  • Olivier Wittenberg (CNRS, Université Sorbonne Paris Nord)

The school will take place at the Domaine de Port aux Rocs, on the seaside: https://www.domaine-portauxrocs.eu/

Organizing committee:
Benoît Bertrand, Frédéric Bihan, Erwan Brugallé, Baptiste Chantraine, Goulwen Fichou, Frédéric Mangolte, Jean-Philippe Monnier, Michele Stecconi

Please, send an email to Michele Stecconi (Michele.Stecconi@univ-nantes.fr) if you plan to participate at the school or/and the conference.
The deadline for registration is May 31st.
Information and registration

Postdoctoral position 12 months

comments

Contact pour la recherche
mehdi.badsi@univ-nantes.fr
Date d'embauche
date de début de Période de publicité
date de fin de période de publicité
Description de l'emploi

Postdoctoral position : Analysis and numerical methods for plasma sheath models

The MUFFIN(MUltiscale and treFFtz for numerIcal traNsport ) ANR project aims at making progress in the numerical simulation of multidimensional kinetic equations. A part of the project is concerned with modeling and accurate numerical simulation of plasma sheaths. Plasma sheaths are non neutral boundary layers that develop when a plasma is in contact with a metallic wall [3, 5, 1]. Their modeling is a challenge and the development of specific numerical methods for their accurate simulations is a bottleneck for global plasmas simulations (specifically in the context of the ITER project [4]). We are seeking a dynamic PhD graduate in applied mathematics, with a tropism for numerical analysis and scientific computing for PDEs. The project will require both theoretical studies and implementation of numerical methods.
Depending on the preference and/or expertise of the applicant, several work leads are possible:

  •  The construction of stationary plasma sheaths in cylindrical geometry.
  •  A linear stability study of plasma sheaths.
  •  The development of compatible semi-Lagrangian schemes for the Vlasov-Ampere equations that preserve a discrete Gauss Law [2].

Location: Laboratoire de Mathématiques Jean Leray, Université de Nantes.
Grant: ANR MUFFIN project.
Advisors: Mehdi BADSI, Christophe BERTHON and Anaïs CRESTETTO
Beginning: September 2021 or October 2021.
Duration: 12 months.
For more information, send an email with your CV, publications
and reference contacts to: mehdi.badsi@univ-nantes.fr

The deadline for applying is June 1rst 2021.

References

[1] M. Badsi, M. Campos Pinto, and B. Despres. A minimization formulation of a bikinetic sheath. Kinetic and related models, 9(4), 2016.

[2] M. Campos-Pinto and E. Sonnendrucker. Compatible maxwell solvers with particles i: conforming and non-conforming 2d schemes with a strong ampere law. SMAI Journal of Computational Mathematics, 3, 2017.

[3] Francis F. Chen. Introduction to Plasma Physics and controlled fusion. Springer, 1984.

[4] ITER. Iter organization.

[5] K.U Riemann. The bohm criterion and sheath formation. Physics of Plasmas, 1991.

Poste pourvu
NON
Type d'emploi
Post Doctorant

Dynamique de concentration dans un modèle de population structuré en âge et en phénotype

Cécile Taing
Etablissement de l'orateur
LMA - Université de Poitiers
Date et heure de l'exposé
Lieu de l'exposé
Zoom Planet
Résumé de l'exposé

Pour illustrer la sélection d'individus les plus adaptés à un environnement donné à partir d'un modèle de population structurée par une variable de trait, on peut étudier la convergence de la distribution de population vers une masse de Dirac concentrée en ce trait adapté. Dans cet exposé, je présenterai des résultats sur le comportement asymptotique de la solution d'une équation structurée en âge et en trait. Dans un premier temps, j'introduirai un modèle simplifié en supposant qu'il n'y pas de mutation. L'analyse de ce modèle repose sur l'étude d'un problème aux valeurs propres paramétré par la variable de trait. Ensuite, je présenterai le modèle avec mutations qui fait apparaître une équation de Hamilton-Jacobi sous contraintes. Il s’agit d’un travail fait en collaboration avec Samuel Nordmann et Benoît Perthame