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<Paper uid="W02-0804">
  <Title>Defining and Representing Preposition Senses: a preliminary analysis</Title>
  <Section position="7" start_page="0" end_page="0" type="evalu">
    <SectionTitle>
5 Evaluation
</SectionTitle>
    <Paragraph position="0"> Let us now evaluate the accuracy of our sense distinctions. For that purpose, we considered 6 among the most frequent and polysemic prepositions, which also undergo a large number of metaphors. Two independent native speakers of French, with some light knowledge of linguistics, have been given a large sample with those prepositions and have been asked to classify them into one of the senses we have established.</Paragraph>
    <Paragraph position="1"> They recieved a minimal explanation of the task in order not to influence their judgments.</Paragraph>
    <Paragraph position="2"> Preposition occurences have been extracted from the French Encyclopedia Universalis, a huge encyclopedia that covers most of the domains, written by a large number of authors.</Paragraph>
    <Section position="1" start_page="0" end_page="0" type="sub_section">
      <SectionTitle>
5.1 Preposition distribution in French
</SectionTitle>
      <Paragraph position="0"> Before making any evaluation, let us say a few words about preposition distribution in French. We have collected 14656 preposition usages which are are distributed as follows:  The other prepositions occur less than 50 times, and in general less than 10 times. If we do not take into account DE and A and their morphological variants, frequencies need to be multiplied by 3.14 (no relation with the number a0 , though). The observation is that 16 prepositions occur more than 1%. They are not necessarily the most polysemic ones (e.g. entre is not very polysemic).</Paragraph>
      <Paragraph position="1"> We have concentrated our evaluation on the other prepositions, which cover about 1/3 of the preposition uses. They are of much interest since they often introduce adjuncts, while de and `a often introduce prepositional arguments of verbs or of predicative nouns. Prepositions introducing adjuncts are of much interest since they are the main linguistic marks that define the role of the NP w.r.t. to a predicate.</Paragraph>
    </Section>
    <Section position="2" start_page="0" end_page="0" type="sub_section">
      <SectionTitle>
5.2 Evaluation of our sense distinctions
</SectionTitle>
      <Paragraph position="0"> Let us now proceed to a preliminary evaluation of our sense distinctions. In order to have a more diverse sample for the 6 prepositions considered in our evaluation, we have considered additional texts from the encyclopedia (about 1200 pages) and texts from other sources (PhDs dissertations, newspapers). W.r.t.</Paragraph>
      <Paragraph position="1"> prepositions uses found in the corpus, we have defined three types of behaviors: (1) the classification into one of the senses we have elaborated is straightforward, (2) the classification is possible but not immediate: for example some pragmatic considerations must be considered or there is a metaphorical or metonymic construction to identify, and (3) classification is not possible at all. This latter case includes, among others, collocations. We get the following preliminary results, where (1), (2) and (3), expressed in %, refer to the 3 criteria above: Fig. 4 - Evaluation of sense distinctions prep. contre vers dans pour sous sur  Situation (2) occurs only with senses having by far a high number of uses (above 30%, but often more).</Paragraph>
      <Paragraph position="2"> There are several reasons to this observation: those senses are in general quite large, with a lot of extensions, metaphors, pragmatic implications and interactions. They often exhibit a large number of uses with abstract NPs. Finally, these senses are perhaps not sufficiently accurately defined.</Paragraph>
      <Paragraph position="3"> Uses that do not fall into any of the senses (case (3)) are often fixed or semi-fixed forms or uses with a heavy pragmatic influence. Semi-fixed forms are, e.g. sous le nom de (under the name of) or sur le plan de, which are forms we have not included into our descriptions. Pragmatic factors are, for example: Pierre a cach'e son livre sous son blouson, where sous (=under his jacket) means dans (=in). Same for La guerre avec l'Allemagne (the war with Germany), where avec characterizes an opposition (contre (against) is more usual), due to the semantics of war, a use that needs some interpretation (there are a few such situations with aggression verbs, where semantic composition is necessary to get the meaning of the expression).</Paragraph>
      <Paragraph position="4"> Finally, another test for sense distinctions we are carrying out is the coordination test where two different senses of a preposition should not, a priori, be coordinated: * Un m'edicament contre la toux et contre l'avis du m'edecin.</Paragraph>
    </Section>
  </Section>
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