#core_group__core__nucleus__nucleu  a small group of indispensable persons or things; "five periodicals make up the core of their publishing program"
  supertype:  set.aggregation  a group of things of the same kind that belong together and are so used: "a set of books"; "a set of golf clubs"; "a set of teeth"
  subtype:  cadre  a nucleus of military personnel capable of expansion

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