Seminars

The GAMP seminar serves as a forum for researchers associated to the group to present their research interests to the community. The talks are intended for a general mathematical audience. All the times below are in Lebanon time (+3GMT).

    • Tuesday January 21, 2020 at 2:00 PM: Florian Bertrand (AUB)
      Place: AUB, BLISS 206
      Title: Introduction to invariant metrics
      Abstract: In this talk, I will survey some of the classical biholomorphically invariant metrics defined on domains in the complex Euclidean space. These metrics and related objects are particularly adapted to study holomorphic maps or the geometry of the corresponding domain.

 

  • Tuesday September 29, 2020 at 2:00 PM : Rafael Andrist (AUB)
    Place: Zoom meeting (click here)
    Title: Vector fields, flows, and automorphisms
    Abstract: We review the notions of vector fields and their flows. Complete vector fields give rise to automorphisms. In the algebraic category, complete vector fields are locally nilpotent derivations, and we can use this well-developed theory to find an abundance of automorphisms.
  • Tuesday December 08, 2020 at 2:00 PM : Alfonso Garmendia (Postdam)
    Place: Zoom meeting (click here)
    Title: Monodromy and Holonomy groupoid for singular foliations
    Abstract:The holonomy groupoid of a singular foliation, given in complete generality by Androulidakis and Skandalis, has been an object of intense study since its appearance. In this talk, I will describe a new construction for this groupoid following the strategy of the classical construction for regular foliations, using paths, and mirroring the integration of Lie algebroids via paths (per Crainic and Fernandes). In this way, there is a characterization of the holonomy and fundamental groupoids of a singular foliation that more clearly reflects the homotopic character of these invariants.

 

  • April 09, 2021 at 2:00 PM : Georges Habib (Lebanese University)
    Place: Zoom meeting (click here)
    Title: Cohomology on foliations.
    Abstract:In this talk, we review the notion of cohomology in the context of foliation. In particular, we define the basic cohomology and the antibasic cohomology and we study the properties for each one.  This is a joint work with Ken Richardson, Texas Christian University.

 

  • Tuesday April 06, 2021 at 2:00 PM : Ihsane Malass (Postdam)
    Place: Zoom meeting (click here)
    Title: The perturbed analytic torsion on a manifold with boundary                      Abstract: This talk concerns the analytic torsion on a Riemannian manifold associated with the de Rham complex. We perturb the de Rham complex by a closed odd form; the resulting analytic torsion then involves a zeta-determinant of the associated perturbed de Rham-Laplace operator. The variation of the perturbed analytic torsion in the boundaryless case had been studied by Mathai and Wu, leading to a generalization of the well-known invariance of the analytic torsion under a variation of the underlying metric. Following work by Cheeger,  we  investigate how the presence of a boundary  affects these results.
  • February 10, 2022 at 3:00/4:00 PM : Pierre Mathieu (Université de Marseille)
    Place: Zoom meeting (click here)
    Title: Random walks on hyperbolic spaces        Abstract: we’ll be looking at random walks on discrete groups that have a nice action of some metric hyperbolic space like, say, fundamental groups of surfaces or mapping class groups.
    The talk will be mainly introductory: I will define such things as Gromov hyperbolic spaces and try to explain the interplay between geometric, dynamical and probabilistic aspects that lie at the core of the proofs of the main results on such random walks: convergence of sample paths, laws of large numbers, central limit theorems and even large deviation properties.
    Eventually, I will mention the latest news on the shape of the large deviation action functional, refereeing to ongoing work with R. Aoun and C. Sert, and related open questions.
  • April 28, 2022 at 3:00 (Germany)/4:00 PM (Beirut): Nguyen Viet DANG (Université Paris Cité)
    Place: Zoom meeting (click here)
    Title: Renormalization of Feynman amplitudes by multiple zeta regularizationAbstract: In joint work with Bin Zhang, we renormalize divergent Feynman amplitudes appearing in Quantum Field Theory by spectral zeta regularization involving many complex parameters. I will explain our results in some pedagogical way and using some examples to illustrate the difficulties.