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<Paper uid="E89-1026">
  <Title>LAMBEK THEOREM PROVING AND FEATURE UNIFICATION</Title>
  <Section position="8" start_page="0" end_page="0" type="evalu">
    <SectionTitle>
7 CONCLUDING
REMARKS
</SectionTitle>
    <Paragraph position="0"> Feature unification can be added to LTP in a simple and straightforward way. Because reduction laws that fall out (including feature unification) as theorems in LTP-FU can account for FOOT phenomena, it is not necessary to 'stipulate' category-valued FOOT features and mechanisms to account for their percolation. Not only reflexives, but also unbounded dependencies can be described without the use of category-valued features. Bouma (1987) shows that the addition of Type 0 features GAP with BASCAT as its value and ISL with ~+,-} as its value are the fea- null in FEAT_NAMES, and this obviously reduces complexity of the unification process. We can add to this that it is possible to develop efficient algorithms and computerprograms for LTP (Moortgat, 1987a; Van der Wouden and Heylen, 1988; Van Paassen, 1988; Bouma, 1989). Therefore LTP-FU is attractive for computational linguistics. null A problem remains with respect to the semantics of reflexives we assume here. A reflexive as zichzelf in (7) can only take a verb as an argument, and not for instance a combination of a subject and a verb (S/NP): the reflexive only operates on a functor with two different A-bound arguments. This implies that it is hard for this kind iVan der Linden (1988a) discusses S-V agreement.</Paragraph>
    <Paragraph position="1"> of category to participate in a Left-to-Right analysis (Ades and Steedman, 1982). A solution could be to describe reflexives syntactically as functors of type (X/NP)\X, that impose reentrance (and not equality) upon the NP argument and some other NP. This implies however that we should not only construct a semantic representation, but also a representation of the syntactic derivation, in order to be able to refer to NP's that have already served as arguments to some functor. Future research will be carried out with respect to this constructive categorial grammar.</Paragraph>
    <Paragraph position="2"> A final remark concerns the notion of category structure taken from Gazdar et al. (1988) and applied here. For an account of modifiers and specifiers, it is necessary to include reentrant features. Therefore the definition of category structure in LTP-FU, but also that in CUG and UCG where reentrance is used as well, necessitates extended versions of the notion Gazdar et al. supply.</Paragraph>
  </Section>
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