{TAIL ~ A priority vector} for {HEAD ~ the combination} of requesters has a sequential list of requester identifiers 
{ TAIL ~ A priority vector } for { HEAD ~ the combination } of requesters has a sequential list of requester identifiers
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH