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<Paper uid="W06-2107">
  <Title>An Ontology-Based View on Prepositional Senses</Title>
  <Section position="3" start_page="45" end_page="46" type="intro">
    <SectionTitle>
2 Approach
</SectionTitle>
    <Paragraph position="0"> We are using a bottom-up approach, in which we manually annotate a corpus3 with semantic relations for all occurences of prepositions that are surrounded by noun phrases. Further we annotate the heads of the surrounding noun phrases with their ontological type and subsequently analyze the result in order to produce ontological constraint rules. The ontology that was used for the ontological type annotation, is the SIMPLE top ontology (Pedersen, 1999; Lenci et al., 2000).</Paragraph>
    <Paragraph position="1"> Relations exist between the entities referred to in discourse, and can exist at different syntactic levels; across sentence boundaries as in Peter owns a pony. It is stubborn , or whithin a sentence, a phrase or a word. The relations can be denoted by different parts of speech, such as a verb, a preposition or an adjective, or they can be implicitly present in compounds and genitive constructions as in Peter's pony.</Paragraph>
    <Paragraph position="2"> The following account is based on the work of (Jensen and Nilsson, 2006): Semantic relations are n-ary (where n[?]1): In the example Peter owns a pony the verb 'owns' denotes a binary relation between Peter and a pony, and in example Peter gave the pony a carrot, the verb 'give' denotes a ternary relation between Peter, the pony and a carrot. In the example The pony in the field the preposition 'in' denotes a binary relation between the pony  running words has been compiled from texts from the domain of nutrition.</Paragraph>
    <Paragraph position="3"> and the field. In the framework of this project, however, we will only consider binary relations denoted by prepositions. Using the algebraic description language OntoLog (Nilsson, 2001), we express binary relations as A[REL:B], where the first argument of the relation, A, relates to the second argument, B, in the manner REL.</Paragraph>
    <Paragraph position="4"> A preposition, however, can be ambiguous in regard to which relation it denotes (we assume a restricted set of possible relations for prepositions, see table 1). As an example, let us consider the Danish preposition i (Eng: in): The surface form i  in 'A i B' can denote at least five different relations between A and B: 1. A patient relation PNT; a relation where one of the arguments' case role is patient, e.g. &amp;quot;aendringer i stofskiftet&amp;quot; (changes in the metabolism).</Paragraph>
    <Paragraph position="5"> 2. A locational relation LOC; a relation that denotes the location/position of one of the arguments compared to the other argument, e.g. &amp;quot;skader i hjertemuskulaturen&amp;quot; (injuries in the heart muscle).</Paragraph>
    <Paragraph position="6"> 3. A temporal relation TMP; a relation that denotes the placement in time of one of the arguments compared to the other, e.g. &amp;quot;generalforsamlingen i 1981&amp;quot; (the general assembly in 1981).</Paragraph>
    <Paragraph position="7"> 4. A property ascription relation CHR; a relation that denotes a characterization relation between one of the arguments and a property, e.g. &amp;quot;antioxidanter i renfremstillet form&amp;quot; (antioxidants in a pure form) 5. A 'with respect to' relation WRT; an underspecified re- null lation that denotes an 'aboutness' relation between the arguments, e.g. &amp;quot;forskelle i saltindtagelsen&amp;quot; (differences in the salt intake) .</Paragraph>
  </Section>
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