I'm reading [$1$] and cannot find the the definition for "$G$-admissible subgroup" where $G$ is a finite $p$-group and $p$ is a prime. Any help would be appreciated. Thank you!
Reference
[1] Ja. G. Berkovic, A generalization of the theorems of Hall and Blackburn and their applications to nonregular p-groups, Math.USSR IZvestija, 5(1971), 829-832.
Edit: The first time this term appears: Let the $p$-group $G$ be endowed with a $p$-group of operators $A$ and let $W$ be some group-theoretic property. Even if $G$ contains a normal $W$-subgroup, it doesn't necessarily contain a normal $A$-admissible $W$-subgroup.
Hope this can facilitate.