Core-free permutable subgroup

Definition
A subgroup of a group is termed a core-free permutable subgroup if it is both core-free (i.e., its defining ingredient::normal core is trivial) and permutable (i.e., quasinormal).

Stronger properties

 * Weaker than::Core-free permutable subnormal subgroup

Weaker properties

 * Stronger than::Core-free subgroup
 * Stronger than::Permutable subgroup