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<Paper uid="P91-1027">
  <Title>AUTOMATIC ACQUISITION OF SUBCATEGORIZATION FRAMES FROM UNTAGGED TEXT</Title>
  <Section position="8" start_page="211" end_page="212" type="relat">
    <SectionTitle>
3 RELATED WORK
</SectionTitle>
    <Paragraph position="0"> Interest in extracting lexical and especially collocational information from text has risen dramatically in the last two years, as sufficiently large corpora and sufficiently cheap computation have become available. Three recent papers in this area are Church and Hanks (1990), Hindle (1990), and Smadja and McKeown (1990). The latter two are concerned exclusively with collocation relations between open-class words and not with grammatical properties. Church is also interested primarily in open-class collocations, but he does discuss verbs that tend to be followed by infinitives within his mutual information framework.</Paragraph>
    <Paragraph position="1"> Mutual information, as applied by Church, is a measure of the tendency of two items to appear near one-another -- their observed frequency in nearby positions is divided by the expectation of that frequency if their positions were random and independent. To measure the tendency of a verb to be followed within a few words by an infinitive, Church uses his statistical disambiguator 2Error rates computed by hand verification of 200 examples for each SF using the tagged mode. These are estimated independently of the error rates for verb detection.</Paragraph>
    <Paragraph position="2">  (Church, 1988) to distinguish between to as an infinitive marker and to as a preposition. Then he measures the mutual information between occurrences of the verb and occurrences of infinitives following within a certain number of words. Unlike our system, Church's approach does not aim to decide whether or not a verb occurs with an infinitival complement -- example (1) showed that being followed by an infinitive is not the same as taking an infinitival complement. It might be interesting to try building a verb categorization scheme based on Church's mutual information measure, but to the best of our knowledge no such work has been reported.</Paragraph>
  </Section>
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