{HEAD ~ The systems} and methods maintain {TAIL ~ varying protection levels} of related objects, such as when nodes of a data structure are protected at the same or greater protection level as their children nodes 
maintain
{ HEAD ~ The systems } and methods maintain { TAIL ~ varying protection levels } of related objects , such as when nodes of a data structure are protected at the same or greater protection level as their children nodes
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH