[geometry-ml:03402] Sam Nariman氏、Emmy Murphy氏 講演会20180710

[Tsuboi, Takashi]

幾何学関係の皆様
トポロジー関係の皆様

以下のようにお知らせしておりましたが、Sam Nariman 氏が
来日できなくなったためSam Nariman 氏の講演会はキャンセルとなりました。

Emmy Murphy 氏（トポロジー火曜セミナー）
は予定通り行います。

坪井　俊


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以下の講演会を行いますのでお知らせします。

坪井俊
＝＝＝＝

2018年07月10日(火)
15:00-16:00   数理科学研究科棟(駒場) 128号室
[講演者] Sam Nariman 氏 (Northwestern University)
[講演題目] On the moduli space of flat symplectic surface bundles
[講演概要]
There are at least three different approaches to construct 
characteristic invariants of flat symplectic bundles. Reznikov 
generalized Chern-Weil theory for finite dimension Lie groups to the 
infinite dimensional group of symplectomorphisms. He constructed 
nontrivial invariants of symplectic bundles whose fibers are 
diffeomorphic to complex projective spaces. Kontsevich used formal 
symplectic geometry to build interesting classes that are not yet known 
to be nontrivial. Also for surface bundles whose holonomy groups 
preserve the symplectic form, Kotschick and Morita used the flux 
homomorphism to construct many nontrivial stable classes.
In this talk, we introduce infinite loop spaces whose cohomolgy groups 
describe the stable characteristic invariants of symplectic flat surface 
bundles. As an application, we give a homotopy theoretic description of 
Kotschick and Morita's classes and prove a result about codimension 2 
foliations that implies the nontriviality of KM classes.


2018年07月10日(火) (トポロジー火曜セミナー）
17:00-18:30   数理科学研究科棟(駒場) 056号室
Tea: Common Room 16:30-17:00
[講演者] Emmy Murphy 氏 (Northwestern University)
[講演題目] Loose Legendrians and arboreal singularities (ENGLISH)
[ 講演概要 ]
Given a Stein manifold X, under what conditions can we ensure that X is 
symplectomorphic to C^n? For n>2 the condition of X being diffeomorphic 
to C^n does not suffice, and many counterexamples have been constructed 
which are detected by symplectic cohomology and the Fukaya category. One 
might conjecture that the diffeomorphism type together with a vanishing 
Fukaya category characterizes C^n. While this question is currently well 
of of reach, we present some new partial results. The main tools we'll 
discuss are arboreal singularities, constructable sheaf theory, and 
loose Legendrians -- and how they fit together to approach this question.