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P.010 / PROJECT2025 — 2026

基于特征标零点素图的零散单群刻画Characterising Sporadic Groups from the Vanishing-Element Prime Graph

Characterising Sporadic Groups from the Vanishing-Element Prime Graph基于特征标零点素图的零散单群刻画

从消失元构成的素图出发,刻画部分零散单群与 Chevalley 群。这项工作带来了一篇并列第一作者、目前在审的论文。

Starting from the graph built on vanishing elements, this project characterises some sporadic simple groups and Chevalley groups — work that produced a joint first-author paper now under review.

角色Role
核心成员Core member
类型Type
科研Research
年份Year
2025 — 2026
Research Figure
P.010-A
Research Figure · placeholder
目录Contents

一个问题:群到底由什么决定

有限群不由它的阶决定,这一点每个试图给群分类的人很早就被告知过。阶只是第一层近似,而且是一层很差的近似。这个方向问的是:除了阶,还有什么能用——具体来说,一个群有多少信息被「它的特征标在哪里取到零」这件事钉住。

想法

让一个特征标在某个元素上取零,就称这个元素是消失元(vanishing element)。把这些元素的阶收集起来;凡是能被同一个消失元的阶同时整除的两个素数就连一条边,剩下的是一张图。它出人意料地刚性:在本项目研究的这些群里,这张图是逼出群本身,而不只是给出提示。

我负责的部分

核心成员。我做的是特征标理论这一侧:从消失元的基本性质出发,推出它们的素图约束住了什么。这个项目是本页其余部分的对立面——没有数据、没有模型,也没有任何「再多收一点数据就能修好」的东西。

结果

一篇论文,《New characterizations of G2(3m)G_2(3^m) via its vanishing elements》,并列第一作者,2025 年 3 月投出,目前在 Czechoslovak Mathematical Journal(Springer,SCIE 收录)在审。

这里要把范围说准:论文题目涉及的是 Chevalley 群这一族的刻画。用素图处理零散单群是本项目更大的方向,属于仍在推进的工作,不作为已完成的结论写在这一页上。

这一页为什么短

数学在论文里,而「写给一般读者看的证明摘要」最后往往只是把命题复述一遍。论文接收之后,链接会放到这里。

目录Contents

The question: what determines a group

A finite group is not determined by its order, and everyone who has ever tried to classify one has been told this early. The order is a first approximation and a poor one. The question this direction works on is what is available instead — in particular, how much of a group is pinned down by where its characters vanish.

The idea

Let a character take the value zero on an element; call that element vanishing. Collect the orders of those elements, join two primes whenever a single vanishing element has an order divisible by both, and what is left is a graph. It is a surprisingly rigid object: for the groups studied here, the graph forces the group rather than merely suggesting it.

My role

Core member. My part was the character-theoretic side — starting from the basic properties of vanishing elements and working out what their prime graph forces. The project is the mathematical counterpart to the rest of the research on this site: no data, no model, and nothing that can be fixed by collecting more of it.

Result

A paper, New characterizations of G2(3m)G_2(3^m) via its vanishing elements, jointly first-authored, submitted in March 2025 and currently under review at the Czechoslovak Mathematical Journal (Springer, SCIE-indexed).

Stated precisely: the title's scope is the characterisation of the Chevalley groups. Working on the sporadic simple groups through the prime graph is the larger direction this project belongs to; that part is still in progress and is not written here as a finished claim.

Why this page is short

The mathematics is in the paper, and a summary of a proof written for a general audience tends to be a summary of the statement instead. When the paper is accepted, the link goes here.