9. Programmed computer apparatus as defined in claim 8 and further comprising a dictionary of words for identifying potential parts of speech for each word in the dictionary, any word not in said dictionary being considered a potential full noun, and wherein said grammatical constraint is that words at particular positions in a derived subsequence being tested potentially are specified parts of speech.
8. Programmed computer apparatus as defined in claim 1 wherein a filtering condition against which each of the derived subsequences is tested by said testing means is a grammatical constraint.