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