On the Bergman Property for the Automorphism Groups of Relatively Free Groups

A group G is said to have the Bergman property (the propertyof uniformity of finite width) if given any generating X withX = X^–1 of G, we have that G = X^k for some natural k,that is, every element of G is a product of at most k elementsof X. We prove that the automorphism group Aut(N) of any infinitelygenerated free nilpotent group N has the Bergman property. Also,we obtain a partial answer to a question posed by Bergman byestablishing that the automorphism group of a free group ofcountably infinite rank is a group of uniformly finite width.     

The Jordan Property for Lie Groups and Automorphism Groups of Complex Spaces

We prove that the family of all connected n-dimensional real Lie groups is uniformly Jordan for every n. This implies that all algebraic (not necessarily affine) groups over fields of characteristic zero and some transformation groups of complex spaces and Riemannian manifolds are Jordan.     

On Orbits of Automorphism Groups

If G is a finite group and if A is a group of automorphisms of G whose fixed point subgroup is C _G (A) then every subgroup F of C _G (A) acts on the set of orbits of A in G. The peculiarities of this action are used here to derive several results on the number of orbits of A in an economical manner.Original Russian Text Copyright © 2005 Deaconescu M. and Walls G. L.__________Translated from Sibirskii Matematicheskii Zhurnal, Vol. 46, No. 3, pp. 533–537, May–June, 2005.     

Reduced 1-cohomology and relative property (T)

Shalom characterized property (T) in terms of the vanishing of all reduced first cohomology for compactly generated groups. We characterize group pairs having the property that the restriction map on all first reduced cohomology vanishes. We show that, in a strong sense, this is inequivalent to relative property (T), even for compactly generated group-pairs.     

On Certain Automorphism Groups of Finitely Generated Groups

Mathematical Notes -     

On Automorphism Groups of Arguesian Lattices

Every (finite) group is isomorphic to the automorphism group of some (finite) subdirectly irreducible Arguesian lattice.     

On The Orders of Automorphism Groups of Finite Groups

In the Kourovka notebook, Deaconescu asks whether |AutG|(|G|)for all finite groups G, where denotes the Euler totient function,and whether G is cyclic whenever |AutG|. Both questions areanswered in the negative in this paper. Moreover, |AutG|/(|G|)can be made arbitrarily small. 2000 Mathematics Subject Classification20E36 (primary), 20F28 (secondary).     

2pq阶群的自同构群

继续「１～２」等的工作,给出了２ｐｑ阶群Ｇ的自同构群ＡｕｔＧ的准确构造。     

On Automorphism Groups of Cyclically Ordered Sets

Siberian Mathematical Journal -     

2—（v，11，1）设计的可解区传递自同构群

设G是一个2—(v，11，1)设计的可解区传递但非旗传递自同构群，且G点一本原则，则v=p^n，G≤AГL(1，p^n)且p≠2。     

2—（v,7,1） 设计的可解区传递自同构群

设G是一个2－（v,7,1)设计的可解区传递自同构群,则G是点－本原,且下列之一成立：（1）v=7^n,G是旗－传递的;（2）v=5^6,G=Z5^6:H,这里H是GL（6,5）的可解且不可约的子群;（3）v=p^n,P≤ALT(1,p^n)。特别地,p≠2且p^n≡1(mod42)。     

2-(v,6,1)设计的可解区传递自同构群

设G是一个2-（v,6,1）设计的可解区传递自同构群,且G非旗传递,则：（1）v＝91,G=Z91×Zd,这里3|d|12;（2）v=pm,G≤AL（1,pm）,之一成立．其中p≠2．当p＝3时,4|m见且m＞4;当p＞5时,pm≡1（mod30）。     

On the Automorphism Groups of Cayley Graphs of Finite Simple Groups

Let G be a finite nonabelian simple group and let be a connectedundirected Cayley graph for G. The possible structures for thefull automorphism group Aut are specified. Then, for certainfinite simple groups G, a sufficient condition is given underwhich G is a normal subgroup of Aut. Finally, as an applicationof these results, several new half-transitive graphs are constructed.Some of these involve the sporadic simple groups G = J₁, J₄,Ly and BM, while others fall into two infinite families andinvolve the Ree simple groups and alternating groups. The twoinfinite families contain examples of half-transitive graphsof arbitrarily large valency.     

On the Automorphism Groups of Affine-Invariant Codes.

Using the classification of finite simple groups, we obtain a condition for a permutation group on a finite field GF(pm) to have the affine group AGL(1,pm) as a subgroup. Applying this result to the automorphism groups of non trivial affine-invariant codes, we prove that these automorphism groups are always subgroups of the general affine group AGL(m,p).     

可除阿贝尔p-群的自同构群

主要探讨了秩大于或者等于p-1的可除阿贝尔p-群的p-自同构群,并且得到这些p-自同构如何作用在该可除阿贝尔p-群上.这些结论有助于进一步理解Cernikov p-群的结构.     

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.