AG Seminar Spring 2017
Student No.:50
Time:Thursday 15:00-16:00, 2017-3-2~2017-7-16
Instructor:Eduard Looijenga, Dun Liang, Quan Xu  
Place:Conference room 4, Floor 2, Jin Chun Yuan West Building
Starting Date:2017-3-2
Ending Date:2017-7-16


Welcome our Algebraic Geometry(AG) Seminar in Spring 2017 !  





Time: Thursday, 15:00-16:00



Place:Conference room 4, Floor 2,JinChunYuan West Building



Speaker: Eduard Looijenga (YMSC)



Title: Some Algebraic Geometry related to the mapping class group



Abstract: Since this talk is aimed at algebraic geometers, we begin with reviewing some basic constructions of Teichmueller theory. We then explain how Hodge theory helps us to understand certain representations of the mapping class group. But this talk is more about open problems than about definitive results.





Time: Thursday, 15:00-16:00


Place: Conference room 4, Floor 2, Jin Chun Yuan West Building


SpeakerSheng-Li Tan (East China Normal University, Shanghai)


Title: Moduli Spaces of Curves and Holomorphic Foliations on an Algebraic Surface.


Abstract: In the 19th century, Darboux, Painlev\’e and Poincar\’e studied differential equations of the first order by using complex algebraic geometry. The set of holomorphic solutions of the differential equation is called a holomorphic foliation. In fact, holomorphic foliations can be viewed as a generalization of pencils of algebraic curves, i.e., fibrations on an algebraic surface. Poincar\’e proposed the following research program.


1)    Study the (topological) properties of families of algebraic curves on a complex algebraic surface, and check if they are the properties of differential equations.


2)Find numerical invariants of complex differential equations.


3)Classify complex differential equations according to their invariants.


4)Characterize those complex differential equations which are algebraically integrable.

5)Apply to some problems on real differential equations.

In this lecture, I will talk about some birational invariants of foliations coming from the moduli spaces of curves.




Date: 2017-03-16


Time: Thursday, 15:00-16:00


Place: Conference Room 4, 2nd Floor, JinChunYuan West Building


Speaker: Chao Zhang, YMSC Tsinghua University


Title: Truncated displays with additional structure and reductions of Shimura varieties


Abstract: The theory of displays, invented by D.Mumford and later developped by P.Norman, T.Zink, and E.Lau, is a Dieudonne theory dealing with p-divisible groups. Truncated displays are introduced by Lau recently to study truncated p-divisible groups, i.e. BT-ms. In this talk, I will explain what are truncated displays, and how to put additional structure on them. Then I will show how to use them to define and study level m tratifications on reductions of Shimura varieties.




Date: 2017-03-09


Time: Thursday, 15:00-16:00


Place: Conference Room 4, 2nd Floor, JinChunYuan West Building


Speaker: Prof. Dasheng Wei, AMSS CAS


Title: Strong approximation for certain norm varieties.


Abstract: In this talk, we will introduce some norm varieties which satisfy weak approximation or strong approximation.These norm varieties are a generalization of universal torsors of Chatelet surfaces. Some applications were also given for rational points and integral points by the descent theory.




Date: 2017-03-02


Time: Thursday, 15:00-16:00


Place: Conference Room 4, 2nd Floor, JinChunYuan West Building


Speaker: Thomas Koberda, University of Virginia US


Title: Quotients of surface groups via TQFT


Abstract: I will show how to construct linear quotients of surface groups which are infinite, and where each simple loop has finite order. As an application, I will construct finite covers of surfaces where the pullbacks of simple loops fail to generate the integral homology. We thus answer questions due to Looijenga. This represents joint work with R. Santharoubane.

Ps: The talk is also very relate to the toplogy, so you are welcome if you are interesting in topology.\




For historical informations and details of this seminar, please see and this webpage will also be updated in this semester.


If you want to give a talk or   invite someone in this series, please contact the authors of this message.

Eduard Looijenga ,

Xu Quan

Liang Dun