有限群的$p$-覆盖远离子群及$S$-拟正规嵌入子群

Let G be a finite group, p the smallest prime dividing the order of G and P a Sylow p-subgroup of G. If d is the smallest generator number of P, then there exist maximal subgroups P1, P2,..., Pd of P, denoted by Md(P) = {P1,...,Pd}, such that di=1 Pi = Φ(P), the Frattini subgroup of P. In this paper, we will show that if each member of some fixed Md(P) is either p-cover-avoid or S-quasinormally embedded in G, then G is p-nilpotent. As applications, some further results are obtained.     

有限群的Sylow-子群的弱s-可补极大子群(英文)

假设G是一个有限群,H是G的一个子群.称H在G是s-置换的,若对G的任意的Sylow-子群Gp,有HG_p=G_pH:称H在G是弱s-可补的,若存在G的子群T使得G=HT且H∩T≤H_(sG),其中H_(sG)是所有包含在H中的G的s-置换子群生成的子群.本文给出了下列定理:设F是一个包含超可解群系u的饱和群系,有限群G有一个正规子群H使得G/H∈F.若F~*(H)的每个Sylow子群的所有极大子群在G中是弱s-可补的,其中F~*(H)是H的广义Fitting子群,则G∈F.它是J.Algebra,2007,315:192-209一文中的Skiba公开问题在极大子群情形下的肯定回答.     

关于加法补集的一个注记(英文)

设A和B是正整数集合,若它们的和A+B=a+b:a∈A,b∈B}包含所有充分大的整数,则称A,B为加法补集.本文推广了陈永高和方金辉关于加法补集的一个结论,特别证明了:存在加法补集A,B满足lim sup_(x→∞)(A(x)B(x))/x=(22)/(13),而且存在无穷多个正整数x使得A(x)B(x)-x=1.     

正规子群求解方法的一个注记

Cayley定理是抽象代数中一个非常重要的定理.因为这个定理建立了抽象的有限群G和一个具体群S_n之间的联系.即G同构于S_n的一个子群.所以,对于S_n的子群的研究就显得尤其重要.但是,在教学实践中,学生只是通过定义来求S_n或是S_n的子群的正规子群往往是很困难的事情.本文给出了在群论和表示论中经常用到求S_n的正规子群的一种方法.通过这种方法,希望可以加深学生对相应知识的理解.     

李超代数的c-可补子代数(英文)

李超代数L的一个子代数B称为c-可补的,若存在L的一个理想B使得L=B+C和B∩C(?)B_L,此处B_L是包含在B且为L的理想中最大的一个,本文把c-可补子代数理论发展到李超代数,并利用它们得到了可解李超代数的一些刻画.同时也得到了E-李超代数的一些性质.     

关于有限群的弱S-可补嵌入子群(英文)

假定H是有限群G的一个子群.如果对于|H|的每个素因子p,H的一个Sylow p-子群也是G的某个s-可换子群的Sylow p-子群,则称H为G的s-可换嵌入子群;如果存在G的子群T使得G=HT并且H∩T≤HG,其中HG为群G含于H的最大的正规子群,则称H为G的c-可补子群;如果存在G的子群T使得G=HT并且H∩T≤Hse,其中Hse为群G含于H的一个s-可换嵌入子群,则称H为G的弱s-可补嵌入子群.本文研究弱s-可补嵌入子群对有限群结构的影响.某些新的结论被进一步推广.     

关于有限群的正规补子群

用(G,H,H_0,π)表示如下构形:H,H_0都是有限群G的子群,且H_0△H和π=π(H/H_0)。对于(G,H,H_0,π),考虑如下条件:(A_0)若H-H_0的两个元π-元h_1,h_2,在G中共轭,则h_1H_0,h_2H_0在H/H_0中共轭。(B_1)设π-元h∈H-H_0,p∈π,如果,则。(B_2)设π-元h∈H-H_0,则(C_G(h):C_H(n))是π′-数,且C_G(h)中恰有|C_G(h)|_(π′)个π′-元,C_H(h)中恰有|C_H(h)|_(π′)个π′-元。(D)若p∈π,则H_0中任一p-元不能与H-H_0中元共轭。(E)((G∶H),(H∶H_0))=1。我们证明若(G,H,H_0,π)满足条件(A_0),(B_1),(D)和(E)或(B_2),(C),(D)和(E),则G有唯一的H_0上H的正规补子群。     

s-空间的一个注记（英文）

本文研究了s-空间的性质.利用加法定理及剩余性质,得到以下结论:(1)如果s-空间X是可数多个度量子空间的并,则X是序列空间;(2)如果非局部紧拓扑群G在某个紧化b G中的剩余是遗传s-空间,则G是可分度量空间或σ-紧空间.以上性质推广了Arhangel’skii关于s-空间的一些已有结论.     

关于C(Ω)中可补子空间的一个注记

本文将指出：对于连续函数空间C（Ω）而言（其中，Ω为某紧度空间），其内任一“（格）理想”必为其（拓扑）可补子空间．     

Fuzzy同余和正规Fuzzy子群(英文)

自从A. Rosenfeld在1971年提出Fuzzy子群的概念以来,在Fuzzy群的研究方面已有不少进展,例如见[1,2,5,6,10,11,14]。另一方面,L.A.Zadeh首创的Fuzzy关系理论的研究也是硕果累累,例如见[3,4,8,12,13,15]。本文通过Fuzzy同余关系和正规Fuzzy子群的相互联系,将这两个方向的研究成果进行“嫁接”和“杂交”,得到许多有趣的结果。主要结果是定理2.7,定理3.1和3.6。本文另一主题是引入T-Fuzzy群的正规T-Fuzzy子群的新概念,当T是正则t-范算子时,得到了T-Fuzzy群的三个同构定理,作者认为它比现有的相应同构定理更为简洁、广泛和自然。     

A Note on Solitary Subgroups of Finite Groups

We say that a subgroup H of a finite group G is solitary (respectively, normal solitary) when it is a subgroup (respectively, normal subgroup) of G such that no other subgroup (respectively, normal subgroup) of G is isomorphic to H. A normal subgroup N of a group G is said to be quotient solitary when no other normal subgroup K of G gives a quotient isomorphic to G/N. We show some new results about lattice properties of these subgroups and their relation with classes of groups and present examples showing a negative answer to some questions about these subgroups.     

A Note on c-Supplemented Subgroups of Finite Groups

A subgroup H of a finite group G is said to be c-supplemented in G if there exists a subgroup K of G such that G = HK and H ∩ K is contained in H _G , where H _G is the largest normal subgroup of G contained in H. In this article, we prove that G is solvable if every subgroup of prime odd order of G is c-supplemented in G. Moreover, we prove that G is solvable if and only if every Sylow subgroup of odd order of G is c-supplemented in G. These results improve and extend the classical results of Hall's articles of (1937) and the recent results of Ballester-Bolinches and Guo's article of (1999), Ballester-Bolinches et al.'s article of (2000), and Asaad and Ramadan's article of (2008).     

p-超循环嵌入子群的一个判别准则

令E是有限群G的一个正规子群,且U是所有有限超可解群的集合.E称为在G中是p-超循环嵌入的,如果E的每个pd-阶的G-主因子是循环的.G的子群H称为在G中是U-Φ-可补充的,如果存在G的一个次正规子群T,使得G=HT,且(H∩T)H_G/H_G≤Φ/(H/H_G)Z_U(G/H_G),其中Z_U(G/H_G)是商群G/H_G的U-超中心.作者证明,如果E的一些p-子群在G中是U-Φ-可补充的,那么E在G中是p-超循环嵌入的.作为应用,得到了有限群是p-超可解的若干判断准则,并且推广了一些已知的结果.     

有限群的弱S-拟正规嵌入子群

群G的子群H称为在G中S-拟正规嵌入的,如果对于任意的素数p||H|,H的Sylow p-子群也是G的某个S-拟正规子群的Sylow p-子群.称群G的子群H在G中弱S-拟正规嵌入,如果存在群G的正规子群T,使得HT■G且H∩T在G中是S-拟正规嵌入的.研究了弱S-拟正规嵌入子群的性质,给出了某些群类的新的特征,并推广了一些已知的结论.     

有限群的弱S-拟正规嵌入子群

群G的子群H称为在G中S-拟正规嵌入的,如果对于任意的素数p| |H|,H的Sylow p-子群也是G的某个S-拟正规子群的Sylow P-子群.称群G的子群H在G中弱S-拟正规嵌入,如果存在群G的正规子群T,使得HT(△)-G且H∩T在G中是S-拟正规嵌入的.研究了弱S-拟正规嵌入子群的性质,给出了某些群类的新的特征,并推广了一些已知的结论.     

Finite Groups with Some S-quasinormally Embedded Subgroups

Suppose that G is a finite group and H is a subgroup of G. H is said to be S-quasinormal in G if it permutes with every Sylow subgroup of G; H is said to be S-quasinormally embedded in G if for each prime p dividing |H|, a Sylow p-subgroup of H is also a Sylow p-subgroup of some S-quasinormal subgroup of G. We investigate the influence of S-quasinormally embedded subgroups on the structure of finite groups. Some recent results are generalized.     

On Hall Normally Embedded Subgroups of Finite Groups

A subgroup H of a finite group G is called Hall normally embedded in G if H is a Hall subgroup of the normal closure H ^G . Groups which contain a Hall normally embedded subgroup of order d for every factor d of | G | are characterized. Such groups are supersolvable with a cyclic nilpotent residual of square-free order.     

On Weakly s-permutably Embedded Subgroups of Finite Groups

Suppose G is a finite group and H is subgroup of G. H is said to be s-permutably embedded in G if for each prime p dividing |H|, a Sylow p-subgroup of H is also a Sylow p-subgroup of some s-permutable subgroup of G; H is called weakly s-permutably embedded in G if there are a subnormal subgroup T of G and an s-permutably embedded subgroup H _se of G contained in H such that G = HT and H ∩ T ≤ H _se . We investigate the influence of weakly s-permutably embedded subgroups on the structure of finite groups. Some recent results are generalized.     

具有弱$s$-置换嵌入子群的有限群

Let P be a Sylow p-subgroup of a group G with the smallest generator number d,where p is a prime.Denote by M_d(P) = {P_1,P_(2,...,)P_d} a set of maximal subgroups of P such that φ(P) = ∩_(n=1)~dP_n.In this paper,we investigate the structure of a finite group G under the assumption that the maximal subgroups in M_d(P) are weakly s-permutably embedded in G,some interesting results are obtained which generalize some recent results.Finally,we give some further results in terms of weakly s-permutably embedded subgroups.