SIGNATURE ISeqUnreduce[from,to]

--

-- Parameter
SORT from to

IMPORT ISeq[from] ONLY iseq

FUN / : (to -> from ** to) ** to -> iseq

-- reduce would combine elements of a sequence to a result
-- unreduce decomposes the result into the first element of the sequence and 
-- an intermediate result, from which the next element is calculated, 
-- and so on ...