event

Séminaire GT3

organisé par l'équipe Géométrie

  • Torsion polynomial functions and essential surfaces

    — Takahiro Kitayama

    10 octobre 2022 - 14:00Salle de séminaires IRMA

    Abstract: In an extension of Culler-Shalen theory for higher dimensional representations every essential surface in a 3-manifold is constructed from an ideal point of its SL_n-character variety for some n. We will discuss how the homology classes of an essential surface constructed in the theory and its boundary are restricted by regularity of certain functions on character varieties at an ideal point. One of such functions is induced by the coefficients of twisted Alexander polynomials of highest degree.
  • Reversibility of isometries

    — Tejbir Lohan

    17 octobre 2022 - 14:00Salle de séminaires IRMA

    Abstract: An element in a group G is called reversible if it is conjugate to its inverse in G. An element in a group G is called strongly reversible if it can be expressed as the product of two involutions in G. It has been a problem of broad interest to classify reversible elements and strongly reversible elements in a group. The first part of the talk will be based on basic notions, examples, and some known results related to the reversibility problem. The second part of the talk will constitute a recent work with Dr. Krishnendu Gongopadhyay, where we classify reversible elements and strongly reversible elements in the isometry groups of Hermitian spaces over the field of complex numbers and the division ring of Hamilton’s quaternions.
  • Espaces de tolérance, de Poincaré jusqu'à nos jours

    — Alexey Sossinsky

    31 octobre 2022 - 14:00Salle de séminaires IRMA

  • à venir

    — Raphaël Alexandre

    7 novembre 2022 - 14:00Salle de séminaires IRMA

  • TBA

    — Ken'ichi Ohshika

    21 novembre 2022 - 14:00Salle de séminaires IRMA

  • Devil’s staircase and modular invariance: from random operators to the Hubbard model on a ring

    — Sergei Nechaev

    16 janvier 2023 - 14:00Salle de séminaires IRMA

    Abstract: I will discuss the spectral statistics of the Anderson-like model with random hopping on a line paying attention to its relationship with some number-theoretic properties of the Riemann-Thomae function and the Dedekind eta-function. I will introduce the generalized Riemann-Thomae function and will show that its integral exhibits the Devil's staircase structure and coincides with the ground state of the Hubbard system of particles on a ring interacting with a long-ranged 1/r-potential.
  • Universal Taylor series in one variable, an open question and approximation in several variables

    — Vassilis Nestoridis

    27 février 2023 - 14:00Salle de séminaires IRMA