Winter 2022/23
  • Joint working group (Bonn-Paris): Topics in hyperkähler geometry. 
Friday 14:00-16:00 The seminar will be organized as a hybrid event. Typically we will have two speakers with talks of 50 min each. In Bonn, the talks will be delivered/streamed in Lipschitz Saal, Endenicher Allee 60.
14 October: This session will be replaced by the seminar talk by Chenyu Bai on Thursday 13 October:
Applications d'Abel--Jacobi des familles lagrangiennes, 14:00 in the Séminaire de géométrie algébrique
21 October: LLV algebra acting in Chow: Talks by G. Oberdieck and Y. Kim (Bonn)
28 October: No seminar (school holidays in France)
04 November: No seminar (school holidays in France)
11 November: This session will be replaced by the seminar talk by Pietro Berri on Thursday 10 November
Kodaira dimension of some moduli spaces of polarized hyperkähler manifolds 14:00 in the Séminaire de géométrie algébrique
18 November: Cones and birational maps. Talks by Francesco Denisi & Yajnaseni Dutta/Dominique Mattei
​25 November: Filtration of Chow groups: Talks by Charles Vial & Zhiyuan Li
02 December: André motives of hyperkähler varieties: Talks by Salvatore Floccari & Andrey Soldatenkov
​09 December: Giulia Saccà: Cancelled
 
 
​12 & 13 January: Special Paris addition:
 
 Thursday:
 E. Shinder (2 pm, in the SGA at ENS): tbc
 Abstract: tbc
 
Rui-jie Yang (4 pm at ENS): The Riemann-Schottky problem via singularities of theta divisors

Abstract: The Riemann-Schottky problem is the problem of determining which principally polarized abelian varieties (PPAV) arise as Jacobians of curves. Riemann showed that the theta divisor on the Jacobian of a hyperelliptic curve has singularity of codimension three. A hundred years later, Debarre conjectured that any irreducible PPAV with such property must come from hyperelliptic curves. In this talk, I will discuss a refinement of this conjecture by Casalaina-Martin and provide a partial solution. To achieve this, we develop a complete theory of higher multiplier ideals for Q-divisors, using Sabbah-Schnell's theory of complex Hodge modules. This is joint work with Christian Schnell.
 Friday:
 Alessio Bottini (10 am Jussieu, salle 411,15-16)
 
 tba
 Gianluca Pacienza (11 am Jussieu, salle 411, 15-16)

zoom: https://uni-bonn.zoom.us/j/62174064883?pwd=TUZiWWFXUXpXcUJIRlJBdzBQUDFyQT09

Meeting-ID: 621 7406 4883

Kenncode: 111260

Winter 2021/22
  • Joint working group (Bonn-Paris): Topics in hyperkähler geometry. 
Friday 10:00-12:00 The seminar will be organized as a hybrid event. In Bonn, the talks will be delivered/streamed in Lipschitz Saal, Endenicher Allee 60.
19 November: Gushel-Mukai varieties I (Pietro Beri & Dominique Mattei) notes
26 November: Derived categories of Gushel-Mukai varieties (Dmitrii Pirozhkov) notes
3 December: Gushel-Mukai varieties II  (Pietro Beri & Olivier Debarre) notes
10 December: Characteristic foliations (Fabrizio Anella & Daniel Huybrechts) notes
17 December: Dual fibrations (Thorsten Beckmann & Daniel Huybrechts) notes
14 January: Vector bundles on hyperkähler manifolds (Alessio Bottini & Emanuele Macrì)
21 January: Integral Hodge conjecture (Ignacio Barros & Claire Voisin)

Zoom: https://uni-bonn.zoom.us/j/99037487887?pwd=TVZkNm9sTXZzMkJPMjNKZjdnTExrUT09

Meeting-ID: 990 3748 7887

Kenncode: 596770

Summer 2021
  • Joint working group (Bonn-Paris): Topics in hyperkähler geometry
 
The notes of the talks can be downloaded here.
 
Friday 10:00-12:00
16 April: F. Anella & D. Huybrechts: Semipositive line bundles (Campana-Peternell-Oguiso and Verbitsky)
23 April: A. Bottini: Looijenga-Lunts algebra and Verbitsky's theorem
30 April: P. Beri & O. Debarre: Betti numbers (Guan, Salamon,...)
14 May: M. Varesco & C. Voisin: Kuga-Satake (classical theory and work of Markman-O'Grady)
21 May: T. Beckmann: Derived categories and derived monodromy (work of Taelman)
4 June: D. Huybrechts & M. Mauri: Lagrangian fibrations (Matsushita, Shen & Yin) 
11 June: G. Oberdieck & J. Song: Representation theory and cohomology (Green-Kim-Laza-Robles)
      

 

 

Fall 2020
  • Joint working group (Bonn-Paris):
Moduli spaces of K3 surfaces and hyperkähler varieties.
  Program
  Friday 10:15-11:45
         
  https://uni-bonn.zoom.us/j/99165206652?pwd=cXFjOVNYWVFoQk1qS25mS21KUVF0dz09
  Meeting-ID: 991 6520 6652
  Code: e(K3^[2])
  Notes of talks:
    Olivier Debarre: NL cycles, pdf
    Emre Sertöz: NL divisors are the coefficients of a modular form, pdf
    Fabrizio Anella: Picard groups and NL cycles on F_g pdf
    Daniel Huybrechts: Hodge line bundle, slides
    Yajnaseni Dutta: Tautological classes pdf
    Emanuele Macrì: Moduli spaces of hyperkähler manifolds pdf
    Thorsten Beckmann & Mirko Mauri: Tautological classes on moduli spaces of hyperkähler manifolds pdf
    Johannes Schmitt: Relations in the tautological ring of the moduli of K3 surfaces pdf
    Georg Oberdieck: Relations in the tautological ring of the moduli of K3 surfaces pdf
    Oishee Banerjee: Picard group of Kg for small g, after Greer, Li, and Tian pdf