Date

May 25, Monday, 10:30--11:30, 2026

Place

Room 206, RIMS

Speaker

Wenda Fang (RIMS, Kyoto University)

Title

QP Structures, Poisson Vertex Algebras, and Applications to Integrable Systems

Abstract

　 In this talk, I will discuss classical (R)-matrices for Lie conformal algebras from the viewpoint of QP-geometry. I will explain how this perspective leads to a Maurer--Cartan description of such structures, and how it can be used to construct integrable systems via a generalized Adler--Kostant--Symes scheme. As an application, I will present an integrable system of Mumford--Beauville type. I will also briefly mention some ongoing directions related to joint work with Noriaki Ikeda.

Date

May 18, Monday, 10:30--11:30, 2026

Place

Room 206, RIMS

Speaker

Ryo Hayami (Nagano University)

Title

Lie group-rack triples and Lie-Leibniz triples -with a view towards an integration theory of embedding tensors-

Abstract

　 Embedding tensors are used in theoretical physics to describe higher gauge structures which are called tensor hierarchies. To understand geometric aspects of tensor hierarchies, we should find how to "integrate" embedding tensors.
A Lie-Leibniz triple is the mathematical formulation of an embedding tensor. In this talk, I will introduce an integrated object of a Lie-Leibniz triple, which we call a Lie group-rack triple. I will show that any real finite-dimensional Lie-Leibniz triple can be integrated to a local Lie group-rack triple. This integration procedure can be seen as a generalization of the Bordemann-Wagemann integration of an augmented Leibniz algebra into an augmented Lie rack.

Date

May 11, Monday, 10:30--11:30, 2026

Place

Room 206, RIMS

Speaker

Naoki Genra (Toyama University)

Title

BRST cohomology for linear quiver gauge theory and associated Poisson vertex algebras

Abstract

　 BRST cohomology is an analogous method with Hamiltonian reductions to obtain new vertex algebras from given ones. Using the construction of physicists, we give the BRST cohomology vertex algebras of 3d N=4 quiver gauge theory, and compute the associated graded Poisson vertex algebras. Then we show how to relate these Poisson vertex algebras to Higgs branches of linear quiver gauge theory.

Date

April 27, Monday, 10:30--11:30, 2026

Place

Room 206, RIMS

Speaker

Leonid Ryvkin (Claude Bernard University Lyon 1)

Title

Tepui fibrations and singular vector bundles

Abstract

　 As a differential-geometric object, a tepui fibration is a type of singular fiber bundle with smooth base space and smooth fibers, however the fiber dimension might jump when moving from one base point to another. Tepui fibrations naturally turn up in differential geometry, when one is quotienting by a smooth family of symmetries, which degenerates at certain points, e.g. in the context of singular foliations. In this talk I will give an introduction to tepui fibrations and show how they provide a natural way to extend the classical Serre-Swan theorem beyond the setting of projective modules.
Based on joint work with Alfonso Garmendia and David Miyamoto, https://arxiv.org/pdf/2510.20936.