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