[geometry-ml:06591] 埼玉大学幾何セミナー【2025年12月1日】

[Toshizumi Fukui]

幾何学メーリングリストの皆様

埼玉大学の福井敏純です．
次の予定で幾何セミナーを行いますのでお知らせします．
重複した情報となりました節はご容赦下さい．

日時: 2025年12月1日(月) 15:00--18:00
場所：数学研究室1（埼玉大学理工学研究科棟5階）

15:00--16:00
Speaker: Goulwen Fichou, University of Rennes
Title: Motivic Milnor fibre and logarithmic geometry

Abstract: We provide a description of the motivic and topological
Milnor fibre of a regular function with only normal crossing
singularities using logarithmic geometry. This approach resembles the
description of the geometry monodromy using real oriented blowing-up
given by Norbert A’Campo in 1975. Joint work with Jean-Baptiste
Campesato and Adam Parusinski.[Coffee Break]

16:30--18:00
Speaker: Masaaki Umehara, Institute of Science Tokyo
Title: Explicit analytic functions defining the images of wave front
singularities

Abstract: We present explicit real-analytic functions whose zero sets
characterize the images of the standard maps of wave-front
singularities. These functions provide realizations of the
“main-analytic sets” introduced by Ishikawa–Koike–Shiota (1984).More
concretely, a subset of Euclidean space is called a “global
main-analytic set” if it can be described, up to a set of smaller
Hausdorff dimension, as part of the zero set of a single real-analytic
function, referred to as its “main-analytic function”.In this talk, we
propose a general framework for constructing such main-analytic
functions by a new method based on explicit computations of resultants.
In particular, we obtain new formulas for the main-analytic functions
associated with the standard maps of wave-front singularities of types
A, D, and E.
I will also explain why these constructions are of interest.

URL: https://rimath-saitama-u.sakura.ne.jp/seminar/kika/2025/11/21/520/