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2.
Jeremy Haefner 《代数通讯》2013,41(8):2765-2782
The following two results are proven.

(i) Let G be a finitely generated torsion-free linear group. If every torsion-free section of G is an R-group, then G is soluble of finite rank. Conversely, if G has finite rank, then it has a subgroup of finite index, in which every torsion-free section is an R-group.

Let G be a finitely generated torsion-free soluble group. If in every torsion-free section of G the normalizer of each isolated subgroup is isolated, then G has finite rank. Conversely, if G has finite rank, then it has a subgroup K of finite index such that in every torsion-free section of K the normalizer of each isolated subgroup is isolated.  相似文献   

3.
    
Abdullah Al-Roqi 《代数通讯》2013,41(6):2040-2051
Let G be a finite group and P a subgroup of order 2. We study in this article the structures of the soluble subgroup of G that is generated by three conjugates of P. We use the results we proved about the soluble subgroups that are generated by three conjugates of P to find a soluble analogue of the Baer–Suzuki Theorem in the case prime 2.  相似文献   

4.
M. González  J. Otal 《代数通讯》2013,41(10):3405-3412

Let A be an elementary abelian group of order at least p 3 acting on a finite p′-group G that is soluble with derived length d. Assume that γ c (C G (a)) has exponent dividing m for any a ∈ A #. It is proved that there exist {p, d, c, m}-bounded numbers c 1 and m 1 such that γ c 1 (G) has exponent dividing m 1.  相似文献   

5.
A group G possesses the property (U) with respect to S if there exists a number M = M(G) such that for each generating set P of the group G there exists an element t ? G for which max x?S |t ?1 xt| P M. It is proved that the well-known Adian-Lisenok groups possess the property (U). In connection with the problem on finding infinite groups with the property (U), which is stated in a joint unpublishedwork by D.Osin and D. Sonkin, it is shown that for any odd n ≥ 1003 there is a continuum set of non-isomorphic, i.e. simple groups with the property (U) in the variety of groups satisfying the identity x n = 1.  相似文献   

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For each countable group we produce a short exact sequence where has a graphical presentation and is f.g. and satisfies property .

As a consequence we produce a group with property  such that is infinite.

Using the tools developed we are also able to produce examples of non-Hopfian and non-coHopfian groups with property .

One of our main tools is the use of random groups to achieve certain properties.

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The ``product replacement algorithm' is a commonly used heuristic to generate random group elements in a finite group , by running a random walk on generating -tuples of . While experiments showed outstanding performance, the theoretical explanation remained mysterious. In this paper we propose a new approach to the study of the algorithm, by using Kazhdan's property (T) from representation theory of Lie groups.

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We study testing properties of functions on finite groups. First we consider functions of the form , where G is a finite group. We show that conjugate invariance, homomorphism, and the property of being proportional to an irreducible character is testable with a constant number of queries to f, where a character is a crucial notion in representation theory. Our proof relies on representation theory and harmonic analysis on finite groups. Next we consider functions of the form , where d is a fixed constant and is the family of d by d matrices with each element in . For a function , we show that the unitary isomorphism to g is testable with a constant number of queries to f, where we say that f and g are unitary isomorphic if there exists a unitary matrix U such that for any . © 2016 Wiley Periodicals, Inc. Random Struct. Alg., 49, 579–598, 2016  相似文献   

9.
群 G 的一个子群 H 称为在 G 中具有半覆盖远离性,如果存在 G 的一个主群列1=G_0< G_1<…<G_1=G,使得对每一 i=1,…,l 或者 H 覆盖 G_j/G_(j-1)或者 H 远离 G_j/G_(j-1).本文证明了予群的半覆盖远离性是子群 C-正规性和子群的覆盖远离性之推广.进一步应用极大子群和 Sylow 子群给出了有限群为可解群的一些特征.  相似文献   

10.
On Finite Groups with Some Semi Cover-Avoiding Subgroups   总被引:1,自引:0,他引:1  
A subgroup H of a finite group G is said to have the semi-cover-avoiding property in G if there is a chief series of G such that H covers or avoids every chief factor of the series. In this paper, some new results are obtained based on the assumption that some subgroups have the semi-cover-avoiding property in the group.  相似文献   

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Let F be a relatively free algebra of infinite rank ?. We say that F has the small index property if any subgroup of Γ = Aut(F) of index at most ? contains the pointwise stabilizer Γ(U) of a subset U of F of cardinality less than ?. We prove that every infinitely generated free nilpotent/abelian group has the small index property, and discuss a number of applications.  相似文献   

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Every non-amenable countable group induces orbit inequivalent ergodic equivalence relations on standard Borel probability spaces. Not every free, ergodic, measure preserving action of on a standard Borel probability space is orbit equivalent to an action of a countable group on an inverse limit of finite spaces. There is a treeable non-hyperfinite Borel equivalence relation which is not universal for treeable in the ordering.

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We prove that all automorphisms of the automorphism group of an infinitely generated free abelian group are inner.  相似文献   

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We examine asymptotic dimension and property A for groups acting on complexes. In particular, we prove that the fundamental group of a finite, developable complex of groups will have finite asymptotic dimension provided the geometric realization of the development has finite asymptotic dimension and the vertex groups are finitely generated and have finite asymptotic dimension. We also prove that property A is preserved by this construction provided the geometric realization of the development has finite asymptotic dimension and the vertex groups all have property A. These results naturally extend the corresponding results on preservation of these large-scale properties for fundamental groups of graphs of groups. We also use an example to show that the requirement that the development have finite asymptotic dimension cannot be relaxed.

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We classify the normal subgroups of of index less than 960; they are all congruence subgroups.

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16.
In the canonical smooth fiber bundles :n+1n, we study generalized differentiable connections constructed by the author in his previous works. Special emphasis is laid on the investigation of the behavior of these connections under local transformations of the classical Poicaré (1,n) and extended Poincaré groups canonically acting in the given connections. We found all the firstorder nonholonomic affine, 1, 2, and 1,2connections with the groups (1,n) and of local transformations and also constructed classes of the corresponding invariant secondorder connections.  相似文献   

17.
In the canonical smooth fiber bundles , we study generalized differentiable connections constructed by the author in his previous works. Special emphasis is laid on the investigation of the behavior of these connections under local transformations of the classical Poincaré groups and extented Poincaré groups canonically acting in the given connections. We found all firstorder nonholonomic affine, connections with the groups and of local transformations and also constructed classes of the corresponding invariant secondorder connections.  相似文献   

18.
In the canonical smooth fiber bundles :n+1n, we study generalized differentiable connections constructed by the author in papers [4] and [5]. Special emphasis is laid on the investigation of the behavior of these connections under local transformations of the classical Poincar{e} groups (1,n) and extended Poincar{e} groups canonically acting in the given connections. We found all first-order nonholonomic affine, 1, 2, and 1,2-connections with the groups (1,n) and of local transformations and also constructed classes of the corresponding invariant second-order connections.  相似文献   

19.
《代数通讯》2013,41(6):2971-2983
Abstract

Let G be a complete monomial group with nilpotent base, namely, G = N wr Sym m , the wreath product of a finite nilpotent group N with the symmetric group on m letters. Then G satisfies the normalizer conjecture for ?G.  相似文献   

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