Tongji Algebraic Geometry Seminar (TAGS)
Currently, the seminar is scheduled to take place from 1-2pm every Friday.
Next seminar:
| Date: | Nov 25, 2022 |
| Speaker: | Yao Yuan(袁瑶), Capital Normal University |
| Title: | TBA |
| Abstract: | TBA |
- Nov 25, 2022
| Speaker: | Yao Yuan(袁瑶), Capital Normal University |
| Title: | TBA |
| Abstract: | TBA |
- Sept 3, 2021
| Speaker: | Heer Zhao(赵和耳), Essen |
| Title: | Degenerating Tamely Ramified Abelian Varieties with Potential Good Reduction via Kummer Log Étale Abelian Varieties |
| Abstract: | Let R be a discrete valuation ring with fraction field K. In this talk, we consider degenerations of a class of abelian varieties over K, namely the ones which admit good reduction over a tamely ramified finite field extension of K. They extend uniquely to “ket log abelian schemes” over R which is regarded as a log scheme with respect to the log structure associated to a chosen uniformizer of R. We will first give a brief introduction to log schemes and Kummer log etale (ket) topology. Then we define ket abelian schemes to be ket sheaves which are (ket) locally just abelian schemes. At last we state and show our degeneration result. |
- Oct 1, 2021 (National Day), no seminar.
- Oct 8, 2021
| Speaker: | Hao Sun(孙浩), Shanghai Normal University |
| Title: | Bridgeland stability conditions on fibred threefolds |
| Abstract: | In this talk, we will introduce the definition of Bridgeland stability conditions on triangulated categories and the recent progress on the construction of Bridgeland stability conditions on fibred threefolds. |
- Oct 15, 2021
| Speaker: | Yang Zhou (周杨), Shanghai Center for Mathematical Sciences |
| Title: | Some wall-crossing techniques in enumerative geometry |
| Abstract: | The theory of Gromov-Witten invariants is a curve counting theory defined by integration on the moduli of stable maps. Varying the stability condition gives alternative compactifications of the moduli space and defines similar invariants. One example is epsilon-stable quasimaps, defined for a large class of GIT quotients. When epsilon tends to infinity, one recovers Gromov-Witten invariants. When epsilon tends to zero, the invariants are closely related to the B-model in physics. The space of epsilon's has a wall-and-chamber structure. In this talk, I will explain how wall-crossing helps to compute the Gromov-Witten invariants and sketch a proof of the wall-crossing formula. |
- Nov 12, 2021
| Speaker: | Zheng Zhang (张正), Shanghai Tech |
| Title: | The Moduli Space of Cubic Surface Pairs Via the Intermediate Jacobians of Eckardt Cubic Threefolds |
| Abstract: | We study the moduli space of pairs consisting of a smooth cubic surface and a transverse plane via a period map. More specifically, the construction associates to a cubic surface pair a so-called Eckardt cubic threefold which admits an involution, and the period map sends the pair to the anti-invariant part of the intermediate Jacobian. Our main result is that the global Torelli theorem holds for the period map (in other words, the period map is injective). The key ingredients of the proof include a description of the anti-invariant part of the intermediate Jacobian as a Prym variety of a branched cover and a detailed study of certain positive dimensional fibers of the corresponding Prym map. This is joint work with S. Casalaina-Martin. |
Organizers: Fangzhou Jin, Lingguang Li, Yinbang Lin, Xiping Zhang, Zili Zhang