Finite groups in which permutability is a transitive relation on their frattini factor groups

Let G be a finite group. A PT-group is a group G whose subnormal subgroups are all permutable in G. A PST-group is a group G whose subnormal subgroups are all S-permutable in G. We say that G is a PT_o-group (respectively, a PST_o-group) if its Frattini quotient group G/Φ(G) is a PT-group (respectively, a PST-group). In this paper, we determine the structure of minimal non-PT_o-groups and minimal non-PST_o-groups.      

On periodic radical groups in which permutability is a transitive relation

A group G is said to be a -group if permutability is a transitive relation in the set of all subgroups of G. Our purpose in this paper is to study -groups in the class of periodic radical groups satisfying min-p for all primes p.     

On finite soluble groups in which Sylow permutability is a transitive relation

A characterisation of finite soluble groups in which Sylow permutability is a transitive relation by means of subgroup embedding properties enjoyed by all the subgroups is proved. The key point is an extension of a subnormality criterion due to Wielandt. This revised version was published online in June 2006 with corrections to the Cover Date.     

Finite rings in which commutativity is transitive

A ring is called commutative transitive if commutativity is a transitive relation on its nonzero elements. Likewise, it is weakly commutative transitive (wCT) if commutativity is a transitive relation on its noncentral elements. The main topic of this paper is to describe the structure of finite wCT rings. It is shown that every such ring is a direct sum of an indecomposable noncommutative wCT ring of prime power order, and a commutative ring. Furthermore, finite indecomposable wCT rings are either two-by-two matrices over fields, local rings, or basic rings with two maximal ideals. We characterize finite local rings as generalized skew polynomial rings over coefficient Galois rings; the associated automorphisms of the Galois ring give rise to a signature of the local ring. These are then used to further describe the structure of finite local and wCT basic rings.     

Finite rings in which commutativity is transitive

A ring is called commutative transitive if commutativity is a transitive relation on its nonzero elements. Likewise, it is weakly commutative transitive (wCT) if commutativity is a transitive relation on its noncentral elements. The main topic of this paper is to describe the structure of finite wCT rings. It is shown that every such ring is a direct sum of an indecomposable noncommutative wCT ring of prime power order, and a commutative ring. Furthermore, finite indecomposable wCT rings are either two-by-two matrices over fields, local rings, or basic rings with two maximal ideals. We characterize finite local rings as generalized skew polynomial rings over coefficient Galois rings; the associated automorphisms of the Galois ring give rise to a signature of the local ring. These are then used to further describe the structure of finite local and wCT basic rings.     

Groups whose non-subnormal subgroups have a transitive normality relation

This article investigates the structure of groups in which every subgroup either is subnormal or has a transitive normality relation, with special attention to the case in which subnormal subgroups have bounded defect.     

Groups with many subgroups having a transitive normality relation

A group is said to be aT-group if all its subnormal subgroups are normal. The structure of groups satisfying the minimal condition on subgroups that do not have the propertyT is investigated. Moreover, locally soluble groups with finitely many conjugacy classes of subgroups which are notT-groups are characterized.     

Groups whose non-normal subgroups have a transitive normality relation

A group is calledmetahamiltonian if all its non-normal subgroups are abelian. The structure of metahamiltonian groups has been investigated by Romalis and Sesekin. In this paper groups are studied in which every non-normal subgroup has a transitive normality relation.     

A note on finite groups in which c-permutability is transitive

A subgroup H of G is c-permutable in G if there exists a permutable subgroup P of?G such that HP=G and H∩P≦H _pG , where H _pG is the largest permutable subgroup of?G contained in?H. A?group G is called CPT-group if c-permutability is transitive in?G. A?number of new characterizations of finite solvable CPT-groups are given.     

Finite groups with transitive semipermutability

A group G is said to be a T-group (resp. PT-group, PST-group), if normality (resp. permutability, S-permutability) is a transitive relation. In this paper, we get the characterization of finite solvable PST-groups. We also give a new characterization of finite solvable PT-groups.      

Permutations which make transitive groups primitive

In this article we look into characterizing primitive groups in the following way. Given a primitive group we single out a subset of its generators such that these generators alone (the so-called primitive generators) imply the group is primitive. The remaining generators ensure transitivity or comply with specific features of the group. We show that, other than the symmetric and alternating groups, there are infinitely many primitive groups with one primitive generator each. These primitive groups are certain Mathieu groups, certain projective general and projective special linear groups, and certain subgroups of some affine special linear groups.     

Finite groups in which every subgroup is a subnormal subgroup or a TI-subgroup

In this paper, we obtain a complete classification of finite groups in which every subgroup is a subnormal subgroup or a TI-subgroup.     

A graph which is edge transitive but not arc transitive

A graph having 27 vertices is described, whose automorphism group is transitive on vertices and undirected edges, but not on directed edges.     

Finite groups in which each subgroup of the commutant is invariant

We study certain properties of finite groups in which each subgroup of the commutant is invariant. Finite nonnilpotent groups with this property are completely described.Translated from Matematicheskie Zametki, Vol. 12, No. 6, pp. 739–746, December, 1972.     

Finite groups in which every self-centralizing subgroup is nilpotent or subnormal or a TI-subgroup

Czechoslovak Mathematical Journal - Let G be a finite group. We prove that if every self-centralizing subgroup of G is nilpotent or subnormal or a TI-subgroup, then every subgroup of G is nilpotent...