First thank you for your support all the time,
My question is, suppose that I have a parent class "Operation" and the subclasses of Operation are "Behavioral Unit", "Behavioral Makro". In my model all objects are instances of the these classes.
I need to get Ids of all objects except the ones from class "Behavioral Unit".

I tried this query but it did not work, I think there is a syntax problem:

  SET aqlGetPredecessorsForObj: ("(<\"Operation\">)+DIFF+(<\"Behavioral Unit\">)")
  CC "AQL" EVAL_AQL_EXPRESSION expr: (aqlGetPredecessorsForObj) modelid: (nGraphModelID)
  SETL lGraphNodeIDs: (objids)

Would you help please?