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  • Lebesgue Master Scholarship
    Nov 15, 2017 to Mar 15, 2018
    lebesgue_money.png The Lebesgue Center offers 10,000€ scholarships to outstanding mathematics students applying for a master programme in mathematics, for a fist year of Master (M1) or for a second year of Master (M2), in Rennes, Nantes, Angers, Brest or Vannes.

    Eligibility

    The stipend is 10,000 euros per year.

    The M1 scholarships are open to all students who have completed a bachelor's degree in mathematics (or related) at the end of the academic year 2016-2017. The applicants for the Lebesgue M1 scholarship should certify a B1 level of proficiency of the French language.
    A student applying for the first year of a master (M1) will be allowed to apply for another scholarship for the second year (M2).

    The M2 scholarships are open to all students who have completed the first year of a master in mathematics (or related) at the end of the academic year 2016-2017.
    The courses of the second year of Master (M2) may be taught in English.

    The application of the Lebesgue scholarship is independent from the application to Masters programmes, whom modalities are indicated in the dedicated websites.

    Deadlines

    The application for the lebesgue Master Scholarship is open until March 15th, 2018.
    The results of the selection process will be edited in April 2017.

    Contact

    Applicants can obtain more information about the masters programmes on the page: Information.

    Application

    Applicants must complete the online form and attach the documents:
    - CV
    - Transcripts
    - Cover letter
    - One or more letters of recommendation.

    Applicants must submit the application only when it is complete. Only electronic submission using the online form will be considered.

    Selection

    The selection will be carried out by the Lebesgue Scientific Committee and the heads of the Masters programmes. It will be based on the academic quality of the applicant.

  • 5 minutes Lebesgue
    Dec 12, 2017

    Les vidéos des exposés seront mises en ligne quelques jours après l'exposé. Vidéothèque

    Prochain exposé : Rediffusion

    12-12-2017:  Thomas Guyard
    Construction du logarithme : Approches historique et mathématique

    Lieu

    Rennes

    Exposés à venir:

    15-12-2017:  François Sauvageot

    19-12-2017:  Guy Casale

    23-01-2017:  Zoïs Moitier

    06-02-2018:  Rozenn Texier-Picard

    20-03-2018:  Loïc Le Marrec

    27-03-2018:  Juliette Bavard

  • Forum Emploi Mathématiques
    Dec 13, 2017

    Forum Emploi Mathématiques (FEM)

    Le FEM connecte les étudiants et les formations en mathématiques aux besoins des entreprises. Le Centre Henri Lebesgue, son Agence de mathématiques pour l'innovation et les formations de Rennes, Brest, Vannes, Nantes et Angers y seront présents.

    Plus d'informations sur le site du Forum Emploi Mathématiques

  • School - Masterclass 2017
    Dec 19, 2017 to Dec 21, 2017

    QR-Code

    Angers, from December 19th to December 21st

    Organization board: Etienne Mann

    We organize a masterclass in Angers, from 19th to 21st of December, 2017. Lectures will be in the morning sessions. We will have two parallel sessions:

    • Etienne Mann : Introduction to algebraic stacks
      We will introduce the notion of fibered category, Grothendieck topology and stacks. We will illustrate these notions on simple examples. These lectures are for Master (or PhD) students who had followed a introduction to algebraic geometry that is algebraic varieties and sheaves.
    • Loic Chaumont: Application of the matrix-tree-theorem

    The organisation board will pay the housing with breakfast and the lunches. The dinners are not payed by the organizers. For the travel expenses, we will do our best in the limit of our budget.

    Deadline 15th novembre. Limit 30 participants maximum.

  • Journée Python et Data Science
    Dec 19, 2017

    Le Groupe Calcul avec le soutien financier de la Mission pour l’interdisciplinarité du CNRS et du Centre Henri Lebesgue, propose une journée consacrée au langage Python, à l'écosystème disponible pour tous les "Data scientists " et à des exemples concrets d'utilisation.

    Le programme: ...

  • Workshop - Numerical methods for algebraic curves
    Feb 19, 2018 to Feb 23, 2018

    Rennes, from February 19th to February 23rd

    Organization board: Xavier Caruso, David Lubicz, Christophe Ritzenthaler, Marie-Françoise Roy

    This workshop will bring together researchers in complex and real algebraic geometry and applied mathematics (physics and cryptography) to discuss numerical methods and open problems on algebraic curves. There will be a number of introductory talks to each of the following topics and invited lectures from specialists: - Theoretical physics/DPE - Computations with the Jacobian - Random real topology - Complexity of computing topology of real algebraic curves - p-adic methods and applications to cryptography

  • Conference - Mathematics and Enterprises Days
    Apr 12, 2018 to Apr 13, 2018

    Vannes, from April 12th to April 13th

    Organization board: Christophe Berthon, Eric Darrigrand, Emmanuel Frénod, Fabrice Mahé, Loïc Chaumont

    Pour répondre aux besoins croissants en moyens de calcul, les entreprises et les laboratoires de recherche développent intensément de nouvelles méthodes numériques, des logiciels et du matériel. L'objectif de ces journées est de permettre aux différents acteurs d'échanger sur les dernières avancées pour améliorer les performances du calcul scientifique. Des exemples d'applications seront présentés dans plusieurs domaines : auto-apprentissage, consommations électriques, télédétection, biologie...
    Ces journées sont organisées par l’agence Lebesgue de mathématiques pour l'innovation dont une des missions est de promouvoir les relations entre les mathématiciens et les scientifiques des entreprises.
    L’Agence est un interlocuteur naturel pour tout acteur du monde industriel confronté à un problème mathématique identifié. Il s’agit d’offrir les meilleures compétences mathématiques disponibles dans les Unités Mixtes de Recherche en Bretagne et Pays de la Loire, en particulier dans le domaine du calcul scientifique.

  • School - Fundamentals and practice of finite elements
    Apr 16, 2018 to Apr 20, 2018

    Roscoff, from April 16th to April 20th

    Organization board: Martin Costabel, Eric Darrigrand, Monique Dauge, Yvon Lafranche

    Scientific board: Monique Dauge (Univ. Rennes 1), Ilaria Perugia (University of Vienna)

    This school will combine high-level courses on theoretical aspects of finite elements, with more practical implementation issues via an open source C++ library . We propose three different activities:

    1) The three main courses (ca 5h each) given by

    Ricardo Nochetto, University of Maryland, USA
    Adaptive Finite Element Methods: Convergence and Optimality

    Paul Houston, University of Nottingham, UK
    Discontinuous Galerkin Finite Element Methods on Polytopic Meshes

    Ralf Hiptmair, ETH Zürich, Suisse
    Boundary Element Methods: Design, Analysis, and Implementation

    2) An initiation to the finite element library XLiFE++ by Eric Lunéville, POEMS team, ENSTA ParisTech, followed by several practical sessions on computers.

    3) A few mini-courses about different related questions (eigenvalues, integral equations, fast methods, singularities) given by members of the organization board.

School - Flows and Limits in Kähler Geometry

List of (confirmed) speakers

Mini-courses :

Talks :

Titles and abstracts

  • Bo Berndtsson (Chalmers University) : Direct image bundles and variations of complex structures

Given a smooth proper fibration $p:\mathcal X\to B$ and $L$ a line bundle over $\mathcal X$, the direct image $$ E:= p_*(L) $$ is in many cases a holomorphic vector bundle over $B$. Its fibers are the spaces of holomorphic sections of $L$ over the fibers of $p$, $X_t=p^{-1}(t)$, and they can be given various $L^2$-metrics. In case the fibration is of relative dimension $n$ so that the fibers are compact Riemann surfaces, special cases of this situation can be used to study the variation of complex structures on the fibers $X_t$. (The fibers are all diffeomorphic, but their complex structure varies with $t$, so we can view the family $X_t$ as a family of variations of complex structures on one fixed smooth manifold.) When the relative dimension is higher than one the situation is more complicated and one needs to consider also higher direct images. I will discuss the problems that arise in this connection, with previous work of Siu, Schumacher and To-Yeung and some recent joint work with Xu Wang and Mihai Paun.

  • Hans-Joachim Hein (Fordham University) : Tangent cones of Calabi-Yau varieties

It has been known for about 10 years that the classical Calabi-Yau theorem on the existence and uniqueness of Ricci-flat Kahler metrics on smooth complex manifolds with zero first Chern class can be extended to a natural setting of weak Kahler metrics on singular complex varieties. However, until relatively recently nothing was known - even in the simplest nontrivial examples - about the precise asymptotic behavior of these weak Ricci-flat metrics at the singularities of the underlying varieties. I will explain work of Donaldson-Sun, H-Naber and H-Sun that resolves this question in certain cases.

  • Valentino Tosatti (Northwestern University) : Metric Limits of Calabi-Yau Manifolds

In this mini-course I will give an introduction to the study of limits of Ricci-flat Kahler metrics on a compact Calabi-Yau manifold when the Kahler class degenerates to the boundary of the Kahler cone. Analytically, the problem is to prove suitable uniform a priori estimates for solutions of a degenerating family complex Monge-Ampère equations, away from some singular set. Geometrically, this can be used to understand the Gromov-Hausdorff limit of these metrics. And if the manifold is projective algebraic and the limiting class is rational, the limits possess an algebraic structure and are obtained from the initial manifold via contraction morphisms from Mori theory.

  • Jeff Viaclovsky (Wisconsin University) : The geometry of SFK ALE metrics

I will discuss some of the basics of scalar-flat Kaehler (SFK) metrics, and focus on the geometry of SFK metrics which are asymptotically locally Euclidean (ALE). These space arise as "bubbles" in the compactness theory of Calabi's extremal Kaehler metrics. I will also present some of the deformation theory of SFK ALE metrics.

  • Thibaut Delcroix (ENS Paris) : Kähler geometry of horospherical manifolds

Horospherical manifolds form a class of almost homogeneous manifolds whose Kähler geometry is very close to that of toric manifolds. They strictly contain homogeneous toric bundles, to which a lot of results holding for toric manifolds have been extended. I will present horospherical manifolds, trying to convince you that they are not much harder to deal with, and in particular I will present the criterion for K-stability in the Fano case that follows either from my work on spherical varieties, or from a direct, Wang-Zhu type, approach.

  • Eleonora Di Nezza (Imperial College) : Monge-Ampère energy and weak geodesic rays

The recent proof of Demailly's conjecture by Witt Nyström gives another evidence that pluripotential theory play a key role when working with complex Monge-Ampère equations in order to solve problems in differential and algebraic geometry. In this talk we investigate pluripotential tools: we characterise Monge-Ampère energy classes in terms of envelopes. And in order to do that, we develop the theory of weak geodesic rays in a big cohomogy class. We also give a positive answer to an open problem in pluripotential theory. This is a joint work with Tamas Darvas and Chinh Lu.

  • Jakob Hultgren (Chalmers University) : Coupled Kähler-Einstein Metrics

A central theme in complex geometry is to study various types of canonical metrics, for example Kähler-Einstein metrics and cscK metrics. In this talk we will introduce the notion of coupled Kähler-Einstein (cKE) metrics which are k-tuples of Kähler metrics that satisfy certain coupled Kähler-Einstein equations. We will discuss existence and uniqueness properties and elaborate on related algebraic stability conditions. (Joint work with David Witt Nyström)

  • Zakarias Sjostrom Dyrefelt (Université de Toulouse) : K-stability of constant scalar curvature Kähler manifolds

In this talk we introduce a variational/pluripotential approach to the study of K-stability of Kähler manifolds with transcendental cohomology class, extending a classical picture for polarised manifolds. Our approach is based on establishing a formula for the asymptotic slope of the K-energy along certain geodesic rays, from which we deduce that cscK manifolds are K-semistable. Combined with a recent properness result of R. Berman, T. Darvas and C. Lu we further deduce uniform K-stability of cscK manifolds with discrete automorphism group, thus confirming one direction of the YTD conjecture in this setting. If time permits we also discuss possible extensions of these results to the case of compact Kähler manifolds admitting holomorphic vector fields.

Partners

Irmar LMJL ENS Rennes LMBA LAREMA

Affiliation

ANR CNRS Rennes 1 Rennes 2 Nantes INSA Rennes INRIA ENSRennes UBO UBS Angers UBL