On the finite groups of supersoluble type

We study the properties of finite groups in which every Sylow subgroup can be connected to the group by a chain of subgroups of prime indices. We establish the solubility of this type of groups. We prove that the class of all finite groups with this property of Sylow subgroups is a saturated hereditary formation. For these groups we find some analogs of the available theorems on the products of normal supersoluble subgroups.     

Finite groups with subgroups supersoluble or subnormal

The aim of this paper is to study the structure of finite groups whose non-subnormal subgroups lie in some subclasses of the class of finite supersoluble groups.     

Finite groups that are products of two normal supersoluble subgroups

Let P₁ be the class of all finite groups that are products of two normal supersoluble subgroups. Let P be the class of all nonsupersoluble P₁-groups G such that all proper P₁-subgroups of G and nontrivial factor groups of G are supersoluble. We classify the P-groups.     

G-covering systems of subgroups for the class of supersoluble groups

Let ? be a class of groups. Given a group G, assign to G some set of its subgroups Σ = Σ(G). We say that Σ is a G-covering system of subgroups for ? (or, in other words, an ?-covering system of subgroups in G) if G ∈ ? wherever either Σ = ? or Σ ≠ ? and every subgroup in Σ belongs to ?. In this paper, we provide some nontrivial sets of subgroups of a finite group G which are G-covering subgroup systems for the class of supersoluble groups. These are the generalizations of some recent results, such as in [1–3].     

有限群的Fuzzy次正规子群与Fuzzy极大子群

本文研究了有限群的Ｆ次正规子群，得出了一个Ｆ子群是Ｆ次正规子群的充要条件，讨论了Ｆ次正规子群的一些重要性质。另外，本文还引入了有限群的Ｆ极大子群的概念，给出了Ｆ子群是Ｆ极大群的充要条件。最后，给出了三个定理，讨论了有限群Ｇ可解、超可解、幂零与Ｇ的Ｆ次正规子群、Ｆ极大子群之间的联系。     

Maximal supersoluble subgroups of symmetric groups

Summary All maximal supersoluble subgroups of symmetric groups are classified.     

两个正规p-超可解子群的积

本文研究了两个正规的p-超可解子群的积构成的极小非P-超可解群的结构的问题.利用有限群论和群类论的一些基本方法,获得了两个正规的p-超可解子群的积仍为P-超可解群的一些充分条件,并推广了文[1]中关于超可解群的情况.     

Products of F*(<Emphasis Type="Italic">G</Emphasis>)-subnormal subgroups of finite groups

A subgroup H of a finite group G is called F*(G)-subnormal if H is subnormal in HF*(G). We show that if a group Gis a product of two F*(G)-subnormal quasinilpotent subgroups, then G is quasinilpotent. We also study groups G = AB, where A is a nilpotent F*(G)-subnormal subgroup and B is a F*(G)-subnormal supersoluble subgroup. Particularly, we show that such groups G are soluble.     

Semilocal rings whose adjoint group is locally supersoluble

An associative ring R, not necessarily with an identity element, is called semilocal if R modulo its Jacobson radical is an artinian ring. It is proved that if the adjoint group of a semilocal ring R is locally supersoluble, then R is locally Lie-supersoluble and its Jacobson radical is contained in a locally Lie-nilpotent ideal of finite index in R.     

On a Class of Supersoluble Groups

This paper identifies a class of supersoluble groups, called finitely generated hallsoging groups. The main result states that the product of a normal finitely generated hall-soging subgroup and a subnormal supersoluble subgroup is always supersoluble.AMS Subject Classification (1991): 20F16, 20F19, 20E25.     

<Emphasis Type="Italic">G</Emphasis>-covering subgroup systems for the classes of supersoluble and nilpotent groups

LetF be a class of groups andG a group. We call a set Σ of subgroups ofG aG-covering subgroup system for the classF (or directly aF-covering subgroup system ofG) ifG ∈F whenever every subgroup in Σ is inF. In this paper, we provide some nontrivial sets of subgroups of a finite groupG which are simultaneouslyG-covering subgroup systems for the classes of supersoluble and nilpotent groups. Research of the first author is supported by the NNSF of China (Grant No. 10171086) and QLGCF of Jiangsu Province and a Croucher Fellowship of Hong Kong. Research of the second author is partially supported by a UGC (HK) grant #2060176 (2001/2002).     

A Generalization of <Emphasis Type="Italic">T</Emphasis>-Groups

This paper identifies a certain class of locally supersoluble groups (called soluble hall-T groups) which contains the soluble T-groups as well as the nilpotent groups. The main result states that the product of a normal soluble hall-T subgroup and a subnormal locally supersoluble subgroup is always locally supersoluble.AMS Subject Classification (1991): 20E25, 20F16, 20F19     

Some criteria for supersolubility in products of finite groups

Let H and T be subgroups of a finite group G. H is said to be permutable with T in G if HT = TH. In this paper, we use the concept of permutable subgroups to give two new criterions of supersolubility of the product G = AB of finite supersoluble groups A and B.      

Mutually permutable subgroups and group classes

We consider the product AB of two finite mutually permutable subgroups A, B and find some subnormal subgroups of the product. This leads to local and otherwise generalized statements about products of supersolvable groups.Received: 19 May 2004     

On a theorem of supersoluble automorphism groups

The maximal nilpotent and supersoluble automorphism groups of Riemann surfaces were given in earlier papers by this author. In this note the author wishes to correct the necessity of the condition given in Theorem (4.3) of Bounds for the order of supersoluble automorphism groups of Riemann surfaces (Proc. Amer. Math. Soc. 108 (1990), 587-600), which was left out at the time of writing the paper. The author also wishes to apologize to the readers for that.

     

Residually Finite Groups with all Subgroups Subnormal

The following result is established. THEOREM. Let G be a periodic, residually finite group with allsubgroups sub-normal. Then G is nilpotent. The well-known groups of Heineken and Mohamed [1] show thatthe hypothesis of residual finiteness cannot be omitted here,while examples in [5] show that a residually finite group withall subgroups subnormal need not be nilpotent. The proof ofthe Theorem will use the results of Möhres that a groupwith all subgroups subnormal is soluble [3] and that a periodichypercentral group with all subgroups subnormal is nilpotent[4]. Borrowing an idea from [2], the plan is to construct certainsubgroups H and K that intersect trivially, and to show thatthe subnormality of both leads to a contradiction. 1991 MathematicsSubject Classification 20E15.     

On complemented subgroups of finite groups

In this paper, it is proved that the class of all finite supersoluble groups with elementary abelian Sylow subgroups is just the class of all finite groups for which every minimal subgroup is complemented. The structure of a finite group under the assumption that all maximal subgroups (respectively 2-maximal) of any Sylow subgroup are complemented is also analyzed.     

Addendum: Posets of Subgroups in p-Groups

A finite group is supersoluble if and only if its poset of subgroups satisfies the Jordan–Dedekind chain condition.     

Torsionsgruppen,deren Untergruppen alle subnormal sind

We prove that a group, which is the extension of a nilpotent torsion group by a soluble group of finite exponent and all of whose subgroups are subnormal, is nilpotent. The problem can be easily reduced to the investigation of extensions of abelian torsion groups by elementary abelian p-groups with all subgroups of these extensions subnormal.     

On finite groups with many supersoluble subgroups

The solubility of a finite group with less than 6 non-supersoluble subgroups is confirmed in the paper. Moreover we prove that a finite insoluble group has exactly 6 non-supersoluble subgroups if and only if it is isomorphic to \(A_5\) or \({{\mathrm{SL}}}_2(5)\). Furthermore, it is shown that a finite insoluble group has exactly 22 non-nilpotent subgroups if and only if it is isomorphic to \(A_5\) or \({{\mathrm{SL}}}_2(5)\). This confirms a conjecture of Zarrin (Arch Math (Basel) 99:201–206, 2012).