Next Seminar
22 October 2025 (Wed) 17:30～(JST)/10:30～(CEST/UTC+2)
Guillaume Tahar (BIMSA)
The affine geometry of meromorphic connections
Abstract :
Any meromorphic connection on the tangent bundle of a Riemann surface defines, away from its poles, a complex affine structure on the surface. Building on this geometric interpretation, we provide the formal and analytic classifications of these poles, as well as their local geometric models. As an application, we show how the Delaunay triangulation of a set of points in the plane admits a broad generalization, yielding a canonical decomposition of any affine surface arising from a meromorphic connection. This is a work in collaboration with Xavier Buff and Arnaud Chéritat.
Painlevé Seminar Topics
Recently, we have encountered many interesting links between differential
equations of Painlevé types and other fields of mathematics such
as algebraic geometry, non-abelian Hodge theory and topological recursion
and so on.
In this web seminar, we will organize research talks on Painlevé
equations and related topics on web (zoom), basically about once every
two or three weeks.
From September 2022, Regular time for seminar talk will be on Wednesday from 17:30--18:30 + discussion time
in JST(Japan) or 10:30--11:30 in UTC+1. We are looking forward to your participation in
the seminar. In order to get zoom access, please register through the form.
List of Talks
You can find the titles and abstracts of all seminars. ⇒ List of Talks
Registration
Online. Please register at the form, we will send you about web seminar address.
Organizers
Arata Komyo (Hyogo), Frank Loray (Rennes 1),
Ryo Ohkawa (Osaka Metropolitan), Masa-Hiko Saito (Kobe Gakuin), Takafumi Matsumoto (RIMS, Kyoto)
Scientific Committee (other than the Organizing Committee)
Supported by
French ANR-16-CE40-0008 project "Foliage" (Frank Loray)
JSPS Grant-in-aid (A) 22H00094 (PI: Masa-Hiko Saito)
Osaka Central Advanced Mathematical Institute:
MEXT Joint Usage/Research Center on Mathematics and Theoretical Physics JPMXP0619217849.
Joyce structures were introduced by T. Bridgeland in the context of the space of stability conditions of a three-dimensional Calabi-Yau category and its associated Donaldson-Thomas invariants, and have also appeared in the context of isomonodromic systems associated with Painlevé equations. Under certain non-degeneracy conditions, they encode a complex hyperkähler structure on the tangent bundle of the base of the Joyce structure. Taking inspiration from this work, I'll give a description of (real) hyperkahler metrics compatible with an integrable system structure that is very similar to the description of Joyce structures. In particular, I will give examples of such hyperkähler metrics where there is a precise analog of the Plebański function appearing in the context of Joyce structures. This is work in progress, which is a follow-up to https://arxiv.org/abs/2403.00548.