Suzuki-Ree群的自同构群的一个新刻画

证明了Suzuki-Ree群²F_4(q),q=2f,2F_4(q),q=2f,²G_2(q),q=32G_2(q),q=3^f及Tits单群f及Tits单群²F_4(2)′的自同构群可由阶分量刻画,其中f=32F_4(2)′的自同构群可由阶分量刻画,其中f=3^s,s为正整数.     

Suzuki-Ree群的自同构群的阶分量刻画

在《数学学报》2013年第56卷第4期中,\"Suzuki-Ree群的自同构群的一个新刻画\"一文证明了Aut(~2^F4(q)),q=2^f和Aut(2^G2(q)),q=3^f,可由其阶分量刻画,其中f=3^s,s为正整数.本文证明了Aut(2^B2(q)),q=2^f和Aut(2G2(q)),q=3^f,也可由其阶分量刻画,其中f为奇素数.结合二者得到结论:Suzuki-Ree单群的所有的素图不连通的自同构群皆可由其阶分量刻画.     

因子von Neumann代数正锥上的凸序列积自同构

设H是复Hilbert空间,M是H上维数大于1的因子von Neumann代数,M₊是M的正锥.设λ∈[0,1],定义Ao_λ=λA^1/2BA^1/2+(1-λ)B^1/2AB^1/2,?A,B∈M₊,称o_λ为M₊上的凸序列积.本文证明了M₊上的凸序列积自同构是由M的一个*-同构或*-反同构实现.     

关于一类自同构群

本文给出了所有Ｐ＾３阶（ｐ为素数）群的自同构群的结构。     

树的自同构群的一个新的恒等式

通过计数给定基础图的标根地图数,本文得到了树的自同构群的如下恒等式∑T∈T(n)Πd∈D(T)^(d-1)！/|AutT|=（2n-1)!/n!(n 1)!,这里T（n),D(T)分别表示n阶不同构树集,树T的次序列。     

交换自同构群的一个重要结论

给出一些新的方法,证明两类交换群不能作为有限群的自同构群,使MacHale提出的问题得到了突破性的进展,所给的方法具有普遍性。     

一类交换群的自同构群

本利用一种新方法,考虑交换群Cp2XCp的自同构群,得到了该自同构群的结构．我们的结论是;     

某些有限群的自同构群

令G是一个奇阶群。本文证明了:当G具有小阶时,G不能作为一个有限群的全自同构群。     

某些有限群的自同构群

证明了: 若n是大于1的奇数, 使得对任意素数p都有p⁴æn, 则不存在有限群G, 使得|Aut(G)| = n.     

Self-Dual Regular 4-Polytopes and Their Petrie-Coxeter-Polyhedra

Coxeter’s regular skew polyhedra in euclidean 4-space IE⁴ are intimately related to the self-dual regular 4-polytopes. The same holds for two of the three Petrie-Coxeter-polyhedra and the (self-dual) cubical tessellation in IE³. In this paper we discuss the combinatorial Petrie-Coxeter-polyhedra associated with the self-dual regular 4-incidence-polytopes.     

一类圈积的自同构群的矩阵描述

使用Bidwell和Curran在2006年引入的描述半直积的自同构的矩阵方法,结合作者等人在2010年证明的关于稳定自同构群的矩阵公式,得到了一类正则圈积的自同构群的矩阵描述,并求出了自同构群的阶.     

A Structural Property of Convex 3-Polytopes

In this paper we prove that each convex 3-polytope contains a path on three vertices with restricted degrees which is one of the ten types. This result strengthens a theorem by Kotzig that each convex 3-polytope has an edge with the degree sum of its end vertices at most 13.     

充当自同构群的有限群的几点注记

设p为奇素数,本文给出了中心循环中心商的阶小于p^5的有限p-群的完全分类并且给出它们中无对合自同构的群的自同构群的阶。由此,我们找到了能作为有限群自同构群的p^mq^n阶群和p^n阶群,统一和推广了Curran在1988年和Caranti与Scoppola在1990年的文章的所有结果。     

Minimal Simplicial Dissections and Triangulations of Convex 3-Polytopes

This paper addresses three questions related to minimal triangulations of a three-dimensional convex polytope P . • Can the minimal number of tetrahedra in a triangulation be decreased if one allows the use of interior points of P as vertices? • Can a dissection of P use fewer tetrahedra than a triangulation? • Does the size of a minimal triangulation depend on the geometric realization of P ? The main result of this paper is that all these questions have an affirmative answer. Even stronger, the gaps of size produced by allowing interior vertices or by using dissections may be linear in the number of points. Received August 16, 1999, and in revised form February 29, 2000. Online publication May 19, 2000.     

Finite Groups of Bounded Rank with an Almost Regular Automorphism of Prime Order

We prove that if a finite group G of rank r admits an automorphism of prime order having exactly m fixed points, then G has a -invariant subgroup of (r,m)-bounded index which is nilpotent of r-bounded class (Theorem 1). Thus, for automorphisms of prime order the previous results of Shalev, Khukhro, and Jaikin-Zapirain are strengthened. The proof rests, in particular, on a result about regular automorphisms of Lie rings (Theorem 3). The general case reduces modulo available results to the case of finite p-groups. For reduction to Lie rings powerful p-groups are also used. For them a useful fact is proved which allows us to glue together nilpotency classes of factors of certain normal series (Theorem 2).     

Approximation for Minimum Triangulations of Simplicial Convex 3-Polytopes

A minimum triangulation of a convex 3-polytope is a triangulation that contains the minimum number of tetrahedra over all its possible triangulations. Since finding minimum triangulations of convex 3-polytopes was recently shown to be NP-hard, it becomes significant to find algorithms that give good approximation. In this paper we give a new triangulation algorithm with an improved approximation ratio 2 - Ω(1/\sqrt n ) , where n is the number of vertices of the polytope. We further show that this is the best possible for algorithms that only consider the combinatorial structure of the polytopes. Received August 5, 2000, and in revised form March 29, 2001, and May 3, 2001. Online publication October 12, 2001.     

4-Dimensional Elation Laguerre Planes Admitting Non-Solvable Automorphism Groups

 This paper concerns 4-dimensional (topological locally compact connected) elation Laguerre planes that admit non-solvable automorphism groups. It is shown that such a plane is either semi-classical or a single plane admitting the group SL(2, ). Various characterizations of this single Laguerre plane are obtained. Received October 17 2000; in revised form April 23 2001 Published online August 5, 2002     

Characterizing Automorphism Groups of Ordered Abelian Groups

A proof is given of the following theorem, which characterizesfull automorphism groups of ordered abelian groups: a groupH is the automorphism group of some ordered abelian group ifand only if H is right-orderable. 2000 Mathematics Subject Classification20K15, 20K20, 20F60, 20K30 (primary); 03E05 (secondary).