GdT: Hodge atoms and irrationality of the very general cubic fourfold

We are organizing two seminar days dedicated to the recent work by Katzarkov, Kontsevich, Pantev and Yu. Discussion will be centered around the preprint  https://arxiv.org/abs/2508.05105.

We will add more information here once the details are finalized.

DAY 1 - 11 December 2025 - JUSSIEU 15-25 101

Schedule:

• 9h00 - 10h30 : Jérémy Guéré
  Introduction to the various ingredients for the proof that a very general cubic fourfold is not rational.

• 11h00 - 12h30 : Felipe Espreafico
  Introduction to GW theory and the different tools to « package » GW invariants in genus 0: quantum D-module, Lagrangian cone, J-function. Statement of Iritani's blow-up formula. 

• 15h30-17h00 : Adrien Sauvaget
  Introduction to Fourier Transform for quantum cohomology. General ideas and constructions (in particular Seidel shifts), and role in the proof of Iritani’s theorem.

Note the Séminaire de Géometrie Algébrique de IMJ-PRG, which will take place from 14h00 to 15h00, with a talk by Andreas Höring.

ZOOM LINK (Day 1): 

https://universite-paris-saclay-fr.zoom.us/j/99403526192

(Meeting Id:  994 0352 6192, Pwd: the number of lines on a quintic threefold, i.e. 2875)

DAY 2 - TBD: The second date (to be confirmed) will be in January.

For any question, do not hesitate to contact: 

Franco Giovenzana (franco dot giovenzana at universite-paris-saclay dot fr), or 

Franco Rota (franco dot rota at universite-paris-saclay dot fr).