In mathematics, in the field of group theory, a component of a finite group is a quasisimple subnormal subgroup.
The product of all the components is the layer of the group.
For finite abelian (or nilpotent) groups, p-component is used in a different sense to mean the Sylow p-subgroup, so the abelian group is the product of its p-components for primes p. These are not components in the sense above, as abelian groups are not quasisimple.
This concept is used in the classification of finite simple groups, for instance, by showing that under mild restrictions on the standard component one of the following always holds:
This group theory-related article is a stub.