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Séminaire ART

organisé par l'équipe Algèbre, représentations, topologie

  • Frédéric Chapoton

    Treillis de Hochschild et polynômes de Coxeter

    6 octobre 2026 - 14:00Salle de séminaires IRMA

    On présentera les treillis de Hochschild et certaines généralisations. Ils sont liés aux polytopes de Hochschild qui ont une origine en topologie algébrique dans les travaux de Saneblidze sur les espaces de lacets libres. On parlera aussi des propriétés observées de leurs polynômes de Coxeter.

  • Dani Kaufman

    Configurations of partial flags and Noncommutative cluster varieties

    13 octobre 2026 - 14:00Salle de séminaires IRMA

    My recent work joint with Zachary Greenberg, Merik Niemeyer and Anna Wienhard constructs noncommutative cluster varieties which parameterize configurations of (decorated) partial flags associated to various algebraic groups. In certain cases these noncommutative cluster varieties are generalizations of those considered by Goncharov and Kontsevich. In particular this means that there is a “spectral description” of these configuration spaces in terms of local systems on certain surfaces. The simplest interesting case is the space of PGL_4 configurations of points of the Grassmannian Gr(2,4), i.e. lines in projective 3 space. In this case, the spectral description can be used to construct a cluster poisson structure on this space and realize its positive points, which parameterize positive configurations of lines, as a fiber bundle over the usual Teichmüller space of a particular surface. I will try to give an overview of this theory and explain how the various cluster structures appearing are related to more well known cluster structures. This work is also motivated by some applications to the computation of scattering amplitudes in N=4 SYM theory, so if there is time I will mention a little bit about this as well.

  • Chris Bowman

    TBA

    3 novembre 2026 - 14:00Salle de séminaires IRMA

    TBA

  • Sinan Yalin

    TBA

    10 novembre 2026 - 14:00Salle de séminaires IRMA

    TBA

  • Thomas Blom

    TBA

    17 novembre 2026 - 14:00Salle de séminaires IRMA

    TBA

  • Emmanuel Wagner

    TBA

    24 novembre 2026 - 14:00Salle de séminaires IRMA

    TBA