{TAIL ~ The program} takes as input an initial data set that contains probabilistic information and returns as output a sequence of {HEAD ~ elementary operations}  
{ TAIL ~ The program } takes as input an initial data set that contains probabilistic information and returns as output a sequence of { HEAD ~ elementary operations }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH