dividing the mail thread into respective segments by analyzing {HEAD ~ the at least two thread body intervals} of {TAIL ~ the thread body field} in the each of the related e mail messages 
of
dividing the mail thread into respective segments by analyzing { HEAD ~ the at least two thread body intervals } of { TAIL ~ the thread body field } in the each of the related e mail messages
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH