the performance of our algorithm on the Brown corpus is as strong as on the WSJ corpus.
for example, in the sequence "...for his stepping...", the pair (for his) is unambiguous in that for has only one possible tag 'IN' and both possible tags of his, 'PRP' and 'PRP$', fall into the Nominal category, then a rule (IN : N ) is extracted; but (his about) is not usable since his has more than one possible tag and about has two possible tags, 'RB' and 'IN', which are neither both 'N' nor both 'V'.