GROUP ACTIONS ON VON NEUMANN REGULAR RINGS

ＧＲＯＵＰＡＣＴＩＯＮＳＯＮＶＯＮＮＥＵＭＡＮＮＲＥＧＵＬＡＲＲＩＮＧＳ￥ＺＨＡＮＧＹＩＮＨＵＯＡｂｓｔｒａｃｔ：ＬｅｔＡｂｅａｒｉｎｇｗｉｔｈｉｎｄｅｎｔｉｔｙ，ＧａｆｉｎｉｔｅｇｒｏｕｐｏｆａｕｔｏｍｏｒｐｈｉｓｍｓｏｆＡ．Ｔｈｅｍａｉｎｒｅｓｕ...     

Some results on domination number of products of graphs

ＳＯＭＥＲＥＳＵＬＴＳＯＮＤＯＭＩＮＡＴＩＯＮＮＵＭＢＥＲＯＦＰＲＯＤＵＣＴＳＯＦＧＲＡＰＨＳＳＨＡＮＥＲＦＡＮＧＳＵＮＬＩＡＮＧＡＮＤＫＡＮＧＬＩＹＩＮＧＡｂｓｔｒａｃｔ．ＬｅｔＧ＝（Ｖ,Ｅ）ｂｅａｓｉｍｐｌｅｇｒａｐｈ．ＡｓｕｂｓｅｔＤｏｆＶｉｓ...     

Two Questions on Local Properties

ＬｅｔＸｂｅａｓｐａｃｅ ,ａｎｄＱａｔｏｐｏｌｏｇｉｃａｌｐｒｏｐｅｒｔｙ .Ｉｆｆｏｒｅａｃｈｘ∈Ｘ ,ｔｈｅｒｅｅｘｉｓｔｓａｎｅｉｇｈｂｏｒｈｏｏｄＵｏｆｘｓｕｃｈｔｈａｔＵｈａｓｐｒｏｐｅｒｔｙＱ ,ｔｈｅｎｗｅｃａｌｌＸａｌｏｃａｌＱ ｓｐａｃｅ .　Ｄｅｆｉｎｉｔｉｏｎ 1　ＡｓｐａｃｅＸｉｓｃａｌｌｅｄθ ｒｅｆｉｎａｂｌｅ,ｉｆｆｏｒｅｖｅｒｙｏｐｅｎｃｏｖｅｒＵｏｆＸｔｈｅｒｅｅｘｉｓｔｓａｓｅｑｕｅｎｃｅ {Ｕｎ}ｏｆｏｐｅｎｒｅｆｉｎｅｍｅｎｔｓｏｆＵｓｕｃｈｔｈａｔｆｏｒｅａｃｈｘ∈Ｘ ,…     

MAXIMUM TREES OF SUBSETS

ＭＡＸＩＭＵＭＴＲＥＥＳＯＦＳＵＢＳＥＴＳＷｕＳｈｉｑｕａｎ（巫世权）（Ｉｎｓｔ．ｏｆＡｐｐｌ．Ｍａｔｈ．，ＣｈｉｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，ＰＯＢｏｘ２７３４，Ｂｅｉｊｉｎｇ１０００８０，Ｃｈｉｎａ）Ａｂｓｔｒａｃｔ：ＬｅｔＸｂｅａｆ...     

WHEN CAN THE STABLE ALGEBRA DETERMINE THE STRUCTURE OF A C^＊-ALGEBRA ？

ＷＨＥＮＣＡＮＴＨＥＳＴＡＢＬＥＡＬＧＥＢＲＡＤＥＴＥＲＭＩＮＥＴＨＥＳＴＲＵＣＴＵＲＥＯＦＡＣ－ＡＬＧＥＢＲＡ？￥ＷＵＬＩＡＮＧＳＥＮＡｂｓｔｒａｃｔ：ＬｅｔＡａｎｄＢｂｅＣ－ａｌｇｅｂｒａｓ．ＳｕｐｐｏｓｅｔｈａｔＫｉｓｔｈｅａｌｇｅｂｒａｏｆａ...     

Theta Subgroups and the Solvability of FiniteGroups

§１．　ＩｎｔｒｏｄｕｃｔｉｏｎａｎｄＤｅｆｉｎｉｔｉｏｎＡｌｌｇｒｏｕｐｓｔｒｅａｔｅｄａｒｅｆｉｎｉｔｅ．Ｉｎ［１］，Ｎ．Ｐ．ＭｕｋｈｅｒｊｅｅａｎｄＰ．Ｂｈａｔｔａｃｈａｒｙａｄｅｆｉｎｅｄｔｈｅｃｏｎｃｅｐｔｏｆθ－ｐａｉｒｓａｓｓｏｃｉａｔｅｄｔｏａｍａｘｉｍａｌｓｕｂｇｒｏｕｐＭｏｆａｇｒｏｕｐＧａｓｆｏｌｌｏｗｓ：ａθ－ｐａｉｒｆｏｒＭｉｓａｎｙｐａｉｒｏｆｓｕｂｇｒｏｕｐｓ（Ｃ，Ｄ）ｏｆＧｓｕｃｈｔｈａｔ（１）ＤＧ，Ｄ＜Ｃ，（２）〈Ｍ，Ｃ〉＝Ｇ，〈Ｍ，Ｄ〉＝Ｍａｎｄ（３）Ｃ／Ｄ…     

Finite Groups with only S-seminormal or Selfnormal Subgroups

Ｆｉｎｉｔｅ　Ｇｒｏｕｐｓ　ｗｉｔｈ　ｏｎｌｙ　Ｓ－ｓｅｍｉｎｏｒｍａｌ　ｏｒ　Ｓｅｌｆｎｏｒｍａｌ　ＳｕｂｇｒｏｕｐｓＦｉｎｉｔｅＧｒｏｕｐｓｗｉｔｈｏｎｌｙＳ－ｓｅｍｉｎｏｒｍａｌｏｒＳｅｌｆｎｏｒｍａｌＳｕｂｇｒｏｕｐｓ￥ＺｈａｎｇＱｉｎｈａｉ...     

SOME RESULTS ABOUT COVERING PROPERTIES OF PRODUCTS

ＳＯＭＥ ＲＥＳＵＬＴＳ ＡＢＯＵＴ ＣＯＶＥＲＩＮＧ ＰＲＯＰＥＲＴＩＥＳ ＯＦ ＰＲＯＤＵＣＴＳ ￥ＪＩＡＮＧＪＩＧＵＡＮＧ;ＴＥＮＧＨＵＩＡｂｓｔｒａｃｔ：Ｔｈｅｆｏｌｌｏｗｉｎｇｒｅｓｕｌｔｓａｒｅｐｒｏｖｅｄ：１．ＬｅｔＸｂｅａｓｃｒｅｅｎ...     

PACKING PAIRS BY QUINTUPLES:THE CASE OF ZERO CONGRUENCE MOD 4

ＰＡＣＫＩＮＧＰＡＩＲＳＢＹＱＵＩＮＴＵＰＬＥＳ：ＴＨＥＣＡＳＥＯＦＺＥＲＯＣＯＮＧＲＵＥＮＣＥＭＯＤ４ＹＩＮＪＩＡＮＸＩＮＧＡｂｓｔｒａｃｔ：ＬｅｔＤ（ｖ）ｄｅｎｏｔｅｔｈｅｍａｘｉｍｕｍｎｕｍｂｅｒｏｆｑｕｉｎｔｕｐｌｅｓｏｆａｖ－ｓｅｔｏｆｐｏ...     

ESTIMATE FOR DISTANCE-COEFFICIENT OF MATRICES

ＥＳＴＩＭＡＴＥＦＯＲＤＩＳＴＡＮＣＥ┐ＣＯＥＦＦＩＣＩＥＮＴＯＦＭＡＴＲＩＣＥＳＬＵＦＡＮＧＹＡＮＡｂｓｔｒａｃｔ．ＭｏｔｉｖａｔｉｏｎｏｆｔｈｉｓｐａｐｅｒｉｓａｎｏｐｅｎｐｒｏｂｌｅｍｅｘｐｏｓｅｄｂｙＢ．Ｂｅａｕｚａｍｙ［１］．ＬｅｔＭｂｅａ...     

非极大交换子群皆正规的有限群

设H是有限群G的一个交换子群.如果H在G中的中心化子正是它本身,则称H为G的极大交换子群.本文主要研究每一非极大交换子群都正规的有限群的结构,对这类有限群给出其完全分类.     

关于有限Abel p-群的自同构群

从有限Abel p-群P的型不变量出发,给出了其自同构群AutP的阶的计算公式,并利用|AutP|的计算公式得到了下面3个结果:1.由有限Abel p-群的型不变量的两种变换得到了其自同构群的阶的变化规律;2.用群的阶、秩、幂指数三个量界定了有限Abel p-群的自同构的阶;3.对部分Frattini子群为p阶群的有限p-群,确定了其自同构群的阶何时达到最小值和最大值.     

Finite groups with abelian second maximal subgroups

Abstract

In this article, we give a complete classification of finite groups whose second maximal subgroups are all abelian.     

Some sufficient conditions on the number of non-abelian subgroups of a finite group to be solvable

Thompson’s theorem indicates that a finite group with a nilpotent maximal subgroup of odd order is solvable. As an important application of Thompson’s theorem, a finite group is solvable if it has an abelian maximal subgroup. In this paper, we give some sufficient conditions on the number of non-abelian subgroups of a finite group to be solvable.     

Splitting Mixed Groups of Finite Torsion-Free Rank

Abstract

First, we give a necessary and sufficient condition for torsion-free finite rank subgroups of arbitrary abelian groups to be purifiable. An abelian group G is said to be a strongly ADE decomposable group if there exists a purifiable T(G)-high subgroup of G. We use a previous result to characterize ADE decomposable groups of finite torsion-free rank. Finally, in an extreme case of strongly ADE decomposable groups, we give a necessary and sufficient condition for abelian groups of finite torsion-free rank to be splitting.     

A New Characterization of Simple K3-groups

ｔｈＮＮＴＷA New Characterization of Simple K_3-groups@王临红&&     

子群为拟正规或自正规的有限群

本文研究了每个子群为拟正规或自正规的有限群，给出了这类群的完全分类，主要结果为定理Ｇ的每个子群为拟正规或自正规当且仅当Ｇ为下列情形之一：Ⅰ）Ｇ为拟Ｈａｍｉｌｔｏｎ群，Ⅱ）Ｇ＝ＨＰ，其中Ｈ为Ｇ的正规ａｂｅｌｉａｎｐ＇－Ｈａｌｌ子群．Ｐ＝〈ｘ〉∈Ｓｙｌ＿ｐ（Ｇ）。〈ｘ￣ｐ〉＝Ｏ＿ｐ（Ｇ）＝Ｚ（Ｇ），ｘ在Ｈ上诱导Ｈ的一个ｐ阶无不动点的幂自同构．ｐ为｜Ｇ｜的最小素因子。由此定理可得文［１］所获得的定理。     

所有子群皆交换或正规的有限群

本文研究所有子群皆交换或正规的有限群. 我们获得了非幂零的情形的一个特征刻画, 也给出了幂零情形的一些性质.     

Functorial topologies and finite-index subgroups of abelian groups

In the general context of functorial topologies, we prove that in the lattice of all group topologies on an abelian group, the infimum between the Bohr topology and the natural topology is the profinite topology. The profinite topology and its connection to other functorial topologies is the main objective of the paper. We are particularly interested in the poset C(G) of all finite-index subgroups of an abelian group G, since it is a local base for the profinite topology of G. We describe various features of the poset C(G) (its cardinality, its cofinality, etc.) and we characterize the abelian groups G for which C(G)?{G} is cofinal in the poset of all subgroups of G ordered by inclusion. Finally, for pairs of functorial topologies T, S we define the equalizer E(T,S), which permits to describe relevant classes of abelian groups in terms of functorial topologies.     

Wonderful blowups associated to group actions

A group action on a smooth variety provides it with the natural stratification by irreducible components of the fixed point sets of arbitrary subgroups. We show that the corresponding maximal wonderful blowup in the sense of MacPherson-Procesi has only abelian stabilizers. The result is inspired by the abelianization algorithm of Batyrev.