On the problem of classification of finite groups associated to multiplicative <Emphasis Type="Italic">η</Emphasis>-products

In this article, we study finite groups such that the cusp forms associated to all elements of these groups by means of some faithful representation are modular forms with multiplicative Fourier coefficients from a special class. The Sylow subgroups of such groups of odd order are found. We consider such metacyclic groups. The groups of order 16 and the groups of order 32 that are metacyclic or are direct products of a group of order 16 and the cyclic group of order 2 are considered in detail. __________ Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 10, No. 4, pp. 43–64, 2004.     

Finite p-groups all of whose non-abelian proper subgroups are metacyclic

In this paper, we classify the finite p-groups all of whose non-abelian proper subgroups are metacyclic and answer a question posed by Berkovich. Received: 22 June 2005     

奇数阶亚循环p-群分类的一个证明

一个有限p群p称为亚循环的,如果P有一个循环的正规子群A,使得PA是循环的.1973年King在文[2]中对亚循环p群进行了分类;在文[4,5]中M.F.NewmanandMingYaoXu发现了这些群的新的表示,给出了新的分类方法,这种方法是由p群生成算法(见文[3])得到的.本文的目的是给这些结果的另一种证明,与p群生成算法是不相关的.     

The Subgroup Normalizer Problem for Integral Group Rings of Some Nilpotent and Metacyclic Groups

For a group G and a subgroup H of G, this article discusses the normalizer of H in the units of a group ring RG. We prove that H is only normalized by the “obvious” units, namely products of elements of G normalizing H and units of RG centralizing H, provided H is cyclic. Moreover, we show that the normalizers of all subgroups of certain nilpotent and metacyclic groups in the corresponding group rings are as small as possible. These classes contain all dihedral groups, all finite nilpotent groups, and all finite groups with all Sylow subgroups being cyclic.     

Intermediately fully invariant subgroups of abelian groups

Describing intermediately fully invariant subgroups of divisible and torsion groups, we show that the intermediately fully invariant subgroups are direct summands in a completely decomposable group whose every homogeneous component is decomposable. For torsion groups, we find out when all their fully invariant subgroups are intermediately fully invariant; and for torsion-free groups, this question comes down to the reduced case. Also, in a torsion group that is the sum of cyclic subgroups, its subgroup is shown to be intermediately inert if and only if it is commensurable with some intermediately fully invariant subgroup.     

ESSENTIALLY FINITELY INDECOMPOSABLE ABELIAN p-GROUPS

Abstract

An abelian p-group C is said to be essentially finitely indecomposable (efi) if given any decomposition of G as the direct sum of a family of subgroups, there exists a positive integer n such that all but at moat a finite number of subgroups of this family are bounded by n. We look at examples and related questions. We prove that a reduced abelian p-group G is efi if and only if G modulo its elements of infinite height is efi. In the proof of this we obtain the following result which is of independent interest: Let A be a reduced p-group with a summand K such that K is a direct sum of cyclic groups. Let B be a basic subgroup of A. Then B contains a subgroup C such that C is a summand of A and the final rank of C is equal to the final rank of K.     

On Complementability of Nonmetacyclic Subgroups in Finite A-Groups

We study groups G that satisfy the following conditions: (i) G is a finite solvable group with nonprimary metacyclic second subgroup and (ii) all Sylow subgroups of the group G are elementary Abelian subgroups. We describe the structure of groups of this type with complementable nonmetacyclic subgroups.     

The Subgroups of Finite Metacyclic Groups

In this paper, the author characterizes the subgroups of a finite metacyclic group K by building a one to one correspondence between certain 3-tuples(k, l, β) ∈ N³ and all the subgroups of K. The results are applied to compute some subgroups of K as well as to study the structure and the number of p-subgroups of K, where p is a fixed prime number. In addition, the author gets a factorization of K, and then studies the metacyclic p-groups, gives a different classification, and describe...     

Finite p-groups whose nonnormal subgroups are metacyclic

For an odd prime p, we give a criterion for finite p-groups whose nonnormal subgroups are metacyclic, and based on the criterion, the p-groups whose nonnormal subgroups are metacyclic are classified up to isomorphism. This solves a problem proposed by Berkovich.     

Ring Isomorphism of Cyclic Cyclotomic Algebras

It is shown that ring isomorphisms between cyclic cyclotomic algebras over cyclotomic number fields are essentially determined by the list of local Schur indices at all rational primes. As a consequence, ring isomorphisms between simple components of the rational group algebras of finite metacyclic groups are determined by the center, the dimension over ?, and the list of local Schur indices at rational primes. An example is given to show that this does not hold for finite groups in general.     

Rational division algebras as solvable crossed products

LetG be a finite group. If there exists a division algebra central over the rationalsQ which is a crossed product forG, then according to a theorem of Schacher, the Sylow subgroups ofG are all metacyclic. The converse is proved here to hold in the following cases: (1)G metacyclic; (2) The Sylow 2-subgroups ofG are cyclic (this impliesG solvable); (3)G is solvable and the Sylow 2-subgroups ofG are dihedral of order larger than 8.     

具有指数为2的循环子群的亚循环群

我们给出了具有指数为2的循环子群的亚循环群的同构分类.这个结果可应用于正则地图的研究中.     

The number of chains of subgroups of a finite cyclic group

T?rn?uceanu and Bentea [M. T?rn?uceanu, L. Bentea, On the number of fuzzy subgroups of finite abelian groups, Fuzzy Sets and Systems 159 (2008) 1084-1096] gave an explicit formula for the number of chains of subgroups in the lattice of a finite cyclic group by finding its generating function of one variable. Using this result T?rn?uceanu [M. T?rn?uceanu, Fuzzy subgroups of finite cyclic groups and Delannoy numbers, European J. Combin. 30 (2009) 283-287] found an explicit formula for the central Delannoy number. In this note we find a generating function of multi-variables for the number of chains of subgroups in the lattice of subgroups of a finite cyclic group. As results we give simplified formulas for the number of chains of subgroups in the lattice of subgroups of a finite cyclic group and for the central Delannoy numbers compared with the formulas given by T?rn?uceanu and Bentea.     

Locally Transitive Graphs Admitting a Group with Cyclic Sylow Subgroups

All graphs are finite simple undirected and of no isolated vertices in this paper. Using the theory of coset graphs and permutation groups, it is completed that a classification of locally transitive graphs admitting a non-Abelian group with cyclic Sylow subgroups. They are either the union of the family of arc-transitive graphs, or the union of the family of bipartite edge-transitive graphs.     

Finite A-groups with complementable nonmetacyclic subgroups

We study groups G that satisfy the following conditions (i) G is a finite solvable group with nonidentity primary metacyclic second commutator subgroup (ii) all Sylow subgroups of G are elementary Abelian. We describe the structure of groups of this type with complementable nonmetacyclic subgroups. __________ Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 58, No. 5, pp. 607–615, May, 2006.     

Finite nondispersible groups all subgroups of which with nonprimary index are metacyclic

We describe the structure of finite nondispersible groups all subgroups of which with nonprimary index are metacyclic.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 47, No. 6, pp. 755–759, June, 1995.     

On the residual finiteness of free products of solvable minimax groups with cyclic amalgamated subgroups

A necessary and sufficient condition for the residual finiteness of a (generalized) free product of two residually finite solvable-by-finite minimax groups with cyclic amalgamated subgroups is obtained. This generalizes the well-known Dyer theorem claiming that every free product of two polycyclic-by-finite groups with cyclic amalgamated subgroups is a residually finite group.