The structure of groups with cyclic commutator subgroups indecomposable to a subdirect product of groups

Abstract

The article studies finite groups indecomposable to subdirect product of groups (subdirectly irreducible groups), commutator subgroups of which are cyclic subgroups. The article proves that extensions of a primary cyclic group by any subgroup of its automorphisms completely describe the structure of non-primary finite subdirectly irreducible groups with a cyclic commutator subgroup. The following theorem is the main result of this article: a finite non-primary group is subdirectly irreducible with a cyclic commutator subgroup if and only if for some prime number $p\geq 3$ it contains a non-trivial normal cyclic $p$-subgroup that coincides with its centralizer in the group. In addition, it is shown that the requirement of non-primality in the statement of the theorem is essential.

Keywords

• group
• cyclic commutator subgroup
• subdirect product of groups
• sylow subgroup
• semidirect product of groups
• centralizer
• group extension
• supersolvable group