Institut de Mathématiques de Marseille, UMR 7373


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17 juin 2019: 3 événements


  • Agenda ERC IChaos

    Du 9 au 22 juin - Alexander BUFETOV & Dmitry ZUBOV

    Research in Pairs & scientific collaboration with Math. Department of University of Cagliari

    Anosov diffeomorphisms are well-known to be strongly mixing.
    It nonetheless remains a challenge to find effective quantitative bounds on the rate of
    mixing for Anosov diffeomorphisms in higher dimension.
    The aim of this collaboration is to use the formalism of holonomy-invariant
    finitely-additive measures on stable foliations of Anosov diffeomorphisms in order to find an effective asymptotic expansion for the equidistribution of their stable leaves.

    Lieu : Hôtel flamingo & University of Cagliari - Sardaigne, Italy

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  • Agenda ERC IChaos

    Du 15 au 21 juin - Adrien BOULANGER

    Scientific collaboration with Math. department (and Gilles COURTOIS)

    Résumé : discussions around Cheeger’s inequality for differential forms

    Lieu : Institut de Mathématiques de Jussieu - Paris

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  • Séminaire Mathématiques et Algorithmique pour la Biologie des Systèmes (MABioS)

    Lundi 17 juin 11:00-12:00 - Maxime LUCAS - IBDM, Aix-Marseille Université

    Network synchronisation with time-varying parameters

    Résumé : Many systems in nature, especially living systems, can be modelled as a collection of interacting oscillators. Such systems can exhibit a plethora of behaviours, amongst which synchronisation, a state of maximal coherence, is of crucial importance. Indeed, the synchronisation of the beat of heart cells is as necessary as the synchronisation of neurons can be a bad pre-seizure sign. So far, ensembles of oscillators have been studied mostly as closed systems so that all parameters such as coupling or frequencies are constant. Very often, however, living systems are open and under the non-negligible influence of their environment, which is in general varying with time. This in turn influence internal parameters of the systems : the frequency of our heartbeat is far from constant, for example. Here, we include time-variability in our mode, and see the effect it has on the dynamics and its stability.
    Here, we will see how time-variability can benefit or reduce stability in two scenarios : a temporal network (time-varying topology), and a network driven by an external oscillator with a time-varying frequency. We will discuss how, in the first case, synchronization is negatively affected, but that the region of synchronization is enlarged in the second case. Moreover, we will discuss the importance of looking into the dynamics of such systems at both short and long timescales. Time-varying features in models of living systems can bring us closer to realistic models, and allow us to reveal richer dynamics resulting from it.

    Lieu : Amphithéâtre Herbrand - I2M Sud, 1st floor 128-130 - Institut de Mathématiques de Marseille (UMR 7373)
    Site Sud - Bâtiment TPR2
    Campus de Luminy, Case 907
    13288 MARSEILLE Cedex 9

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  • 17 juin 2019: 2 événements

    Manifestation scientifique

    • Manifestations scientifiques (colloques, écoles,...)

      Du 10 au 21 juin - INTERNATIONAL CONFERENCE

      Probability and quantum field theory : discrete models, CFT, SLE and constructive aspects

      Topics :
      - Conformal field theories : probabilistic and algebraic aspects
      - Constructive quantum field theory (path integral, regularity structures,...)
      - Discrete models of statistical mechanics (percolation, Ising, FK model,...)
      - SLE/CLE theory
      - Random planar maps
      - 2d quantum gravity
      The conference includes 5 mini-courses (3h each) :
      - Vincent Beffara - Damien Gayet : random nodal lines
      - Jeremie Bouttier : Schur processes and free fermions
      - Alexey Litvinov : Liouville conformal blocks and the AGT conjecture
      - Xin Sun : Liouville quantum gravity as mating of trees
      - Alessandro Vichi : 3d conformal bootstrap
      Organizers :
      - Christophe Garban (Université Lyon 1, France)
      - Rémi Rhodes (I2M, université Aix-Marseille, France)
      - Vincent Vargas (Ecole Normale Supérieure de Paris, France)
      Sponsors :
      - Agence Nationale de la Recherche (ANR)
      - Centre National de la Recherche Scientifique (CNRS)
      - European Research Council (ERC)

      JPEG - 111.6 ko

      Autre lien : IGESA

      Lieu : Île de Porquerolles - Hôtel Club Igesa
      Rue de la Douane
      84300 Hyères

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    • Manifestations scientifiques (colloques, écoles,...)

      Du 17 au 21 juin - INTERNATIONAL CONFERENCE

      Aspects of Non-Positive and Negative Curvature in Group Theory

      This conference will focus on applications of non-positive and negative curvature to geometric group theory. The most well known examples of this are δ-hyperbolic and CAT(0)-groups. More recently, some of the techniques that have been used to study these groups have been imported to study groups that have some features of negative curvature but aren’t themselves negatively curved. For example, the mapping class group is neither δ-hyperbolic nor CAT(0) but major progress has been obtained in on our understanding of this group by studying its action on the δ-hyperbolic curve complex. A related group is Out(Fn), the group of automorphisms of the rank n free group and similar program is underway to understand it. More generally, large classes of groups have been identified that have certain features of negative curvature and this has been exploited to prove results which were heretofore only known in special cases. This conference will bring together a distinguished international group of mathematicians to report on current work and to explore future directions in this active and expanding area of research.
      The conference will also be an opportunity to celebrate the Mladen Bestvina’s contributions to mathematics.
      Speakers :
      - Yael Algom-Kfir (University of Haifa)
      - Martin Bridson (University of Oxford)
      - Indira Chatterji (Université Nice Sophia Antipolis)
      - Matt Clay (University of Arkansas)
      - Mark Feighn (Rutgers-Newark University)
      - Koji Fujiwara (Kyoto University)
      - Vincent Guirardel (Université de Rennes 1)
      - Ursula Hamenstädt (Rheinische Friedrich-Wilhelms-University Bonn)
      - Camille Horbez (CNRS / Université Paris-Sud)
      - Kasia Jankiewicz (University of Chicago)
      - Fanny Kassel (CNRS / IHES)
      - Ian Leary (University of Southampton)
      - Lars Louder (University College London)
      - Frédéric Paulin (Université Paris-Sud)
      - Beatrice Pozzetti (Heidelberg University)
      - Piotr Przytycki (McGill University)
      - Eliyahu Rips (The Hebrew University of Jerusalem)
      - Zlil Sela (The Hebrew University of Jerusalem)
      - Alessandro Sisto (ETH Zurich)
      - Juan Souto (Université de Rennes 1)
      - Karen Vogtmann (University of Warwick)
      - Shmuel Weinberger (University of Chicago)
      Organizers :
      - Kenneth Bromberg (University of Utah)
      - Arnaud Hilion (I2M, Aix-Marseille Université)
      - Ilya Kazachkov (IKERBASQUE. Basque Foundation for Science)
      - Michah Sageev (Technion - Israel Institute of Technology)
      - Jing Tao (University of Oklahoma)
      Sponsors :
      - ANR DAGGER
      - Centre International de Rencontres Mathématiques (CIRM)
      - European Research Council (ERC)
      - Institut de Mathématiques de Marseille (I2M)
      - LabEx Archimède
      - National Science Foundation (NSF)

      JPEG - 22.8 ko

      Autre lien : CIRM

      Lieu : CIRM - 163 avenue de Luminy
      Case 916
      13288 MARSEILLE - Cedex 9

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