【报告信息】
报告1：
报告题目：Groups with restrictions on the set of conjugacy classes sizes
报告人：Ilya Gorshkov (Sobolev Institute of Mathematics, Novosibirsk, Russia)
报告时间：2026-05-20 14:30-15:20
报告摘要：
This talk is devoted to the problem of reconstructing the structure of a finite group from its invariant $N(G)$—the set of conjugacy classes sizes. We will consider questions about how uniquely this set of numbers determines the group, especially in the class of groups with trivial center. The main topics of the talk are:
1. Graph Methods: Introduction and use of various graphs on the set $N(G)$ for group structure analysis, such as the divisibility graph and the prime graph.
2. Special Classes of Groups: Investigation of the properties of $CH$-groups and $SP$-groups.
3. Nilpotency Problem: We discuss Camina's conjecture on whether the nilpotency of a group $G$ follows from the coincidence of its $N(G)$ with $N(H)$, where $H$ is a nilpotent group.
报告2：
报告题目：Recognition of finite simple groups by element orders
报告人：Maria Grechkoseeva (Sobolev Institute of Mathematics, Novosibirsk, Russia)
报告时间：2026-05-20 15:30 -16:20
报告摘要：
Given a finite nonabelian simple group $L$, what can we say about the structure of a finite group $G$ having the same set of element orders as $L$? By 2013, the question has been solved for alternating and sporadic groups, and the result is that $G$ is isomorphic to $L$ unless $L$ is one of three exceptions. By 2015, it has been solved for exceptional groups of Lie type, and the result is that $G$ is an almost simple group with socle isomorphic to $L$, with one exception. This year, we have completed the case of classical groups, and the main goal of this talk is to present the solution and explain the key ideas of the proof.
【线下活动教室】
智华楼413号教室
【线上ZOOM会议链接】
会议链接：https://us02web.zoom.us/j/83690328797?pwd=am1JjwGhpqzYy8Z2Lcct21uqfwuiAw.1
会议号: 836-9032-8797 ，密码: 340130
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【报告信息】
报告主持人：张继平老师
报告题目：Arithmetic invariants for finite simple and related groups
报告人：Andrey V. Vasil'ev (Sobolev Institute of Mathematics, Novosibirsk, Russia)
报告时间：14:30-15:30
报告摘要：
Abstract: Like primes in number theory, simple groups lie in the core of finite group theory. The same remains true for groups closely related to simple groups: almost simple, quasisimple and so on. Attempts to characterize such groups in the class of all finite groups in one way or another have been made many times and became especially persistent since the classification theorem was announced and the complete list of simple groups became available. In this talk we address the problems of characterization of simple and related groups by various arithmetic invariants. We come with some uniform way to think about such sort of problems and discuss what has been already done and what we still do not know but wish to know in this field.
【线下活动教室】
智华楼413号教室
【线上ZOOM会议链接】
会议开始时间：2026年4月15日 02:00 下午
会议链接：https://us02web.zoom.us/j/83690328797?pwd=am1JjwGhpqzYy8Z2Lcct21uqfwuiAw.1
会议号: 836-9032-8797
密码: 340130
