DRC-subgroup

Symbol-free definition
A subgroup of a group is said to be a DRC-subgroup if its characteristic closure is the direct product of itself with subgroups isomorphic to it, viz its characteristic closure is a direct power of it, or equivalently, if it is a direct root in its characteristic closure.

Stronger properties

 * Direct root
 * Characteristic subgroup
 * Minimal normal subgroup:

Weaker properties

 * DFC-subgroup
 * 2-subnormal subgroup