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<Paper uid="P85-1011">
  <Title>SOME COMPUTATIONAL PROPERTISS OF TREE ADJOINING GRAMM.~.S*</Title>
  <Section position="3" start_page="0" end_page="82" type="intro">
    <SectionTitle>
1. INTRODUCTION
</SectionTitle>
    <Paragraph position="0"> lnvestigatiou of constrained grammatical system from the point of view of their linguistic &amp;leqnary and their computational tractability has been a mnjor concern of computational linguists for the last several years. Generalized Phrase Structure grammars (GPSG), Lexical Functional grunmmm (LFG), Phrm~ Linking grammars (PLG), and Tree Adjoining grammars (TAG) are some key examples of grammatical systems that have been and still continue to be investignted along theme lines.</Paragraph>
    <Paragraph position="1"> Some of the bask notions of TAG's were introduced in \[Joahi, Levy, and Takahashi,1975\] and \[Jo~hi,198,3 I. Some pretiminav/ investigations of the linguistic relevance and some computational properties were also carried out in \[Jo~hi, l~S3 I. More recently, a detailed iuvestigution of the linguistic relevance of TAG's were carried out by \[Kro~h and Joshi, 19851.</Paragraph>
    <Paragraph position="2"> In this paper, we will desC/ribe some new results for TAG's, especially in the following areas: (I) parsing complexity of TAG's, (2) some closure results for TAG's, and (3) the relationship to Head grammar*. These topics will be covered in Sections 3, 4, and $ respectively. In section 2, we will give an introduction to TAG's. In section 6, we will state some properties not discussed here. A detailed exposition of these results is given in \[Vijay-Sbuh~ and Joahi,1985\[. *This work wu ptrtisJ~ su.~ported by NSP Gr~u~* Mk'TS-4~IOII6.~'~R, MCS42-07.~94. We wtat to thank Clr |Pol!ard. Kelly Rozeh, David Se~ tad David Weu'. We have beDeflt~l enormously I:y v*/uablo di~*eo~iotc with them.</Paragraph>
  </Section>
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