## 学术报告信息通知

Dear colleagues!

We cordially invite you to take part in an online Algebra Seminar, which will be held online on 13 October 2021. Dr. Egor Voronetsky, a PhD student of Nikolai Vavilov in Saint Petersburg University, will give a talk on the odd unitary groups. Dr. Raimund Preusser, who obtained his Doctor degree from Bielefeld University, is currently a postdoc at the St. Petersburg State University, and will give a talk on Sandwich classification in classical-like groups.

https://zoom.us/j/83289582840?pwd=SFZkSDlrM0VyUXQxS1F6ZDJCSUZ0dz09

Speakers:

1) Egor Voronetsky (PhD student of Nikolai Vavilov in Saint Petersburg University, Russia)

Title:  Odd Unitary groups

Abstract:  Unitary groups are a generalization of the classical groups GL(n, K), O(n, K), and Sp(n, K). They may be defined in terms of an involution ring with a form parameter. More recent and more general constructions of so-called odd unitary groups are due to V. Petrov and myself. Ultimately, the construction via new algebraic objects called odd form rings allow to describe, for example, all fppf twisted forms of the classical group schemes. In the talk I am going to give the details of these constructions.

2) Raimund Preusser

Title:  Sandwich classification in classical-like groups revisited
Abstract:  It follows from the Sandwich Classification Theorem for general linear groups that if $\sigma\in GL_n(R)$, where $R$ is a commutative ring and $n\geq 3$, then any elementary transvection $t_{kl}(\sigma_{ij})~(i\neq j,k\neq l)$ can be expressed as a product of $E_n(R)$-conjugates of $\sigma$ and $\sigma^{-1}$. This talk will be concerned with finding the optimal bound for the number of factors needed for such an expression. Analogues of this problem in other classical-like groups will also be discussed.

Contact:

Jun Hu (Beijing Institute of Technology), junhu404@bit.edu.cn
Zuhong Zhang (Beijing Institute of Technology), zuhong@hotmail.com
Yang Huilei (Beijing Institute of Technology), yanghuilei@bit.edu.cn
Tel.: +86-010-81384701