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Distribution of Complementizers

Like other non-arguments, complementizers anchor an auxiliary tree (shown in Figure 8.1) and adjoin to elementary clausal trees. The auxiliary tree for complementizers is the only alternative to having a complementizer position `built into' every sentential tree. The latter choice would mean having an empty complementizer substitute into every matrix sentence and a complementizerless embedded sentence to fill the substitution node. Our choice follows the XTAG principle that initial trees consist only of the arguments of the anchor8.6 - the S tree does not contain a slot for a complementizer, and the $\beta $COMP tree has only one argument, an S with particular features determined by the complementizer. Complementizers select the type of clause to which they adjoin through constraints on the <mode> feature of the S foot node in the tree shown in Figure 8.1. These features also pass up to the root node, so that they are `visible' to the tree where the embedded sentence adjoins/substitutes.
  
Figure: Tree $\beta $COMPs, anchored by that
\includegraphics[height=3.22in]{/mnt/linc/xtag/work/doc/tech-rept/ps/sent-comps-subjs-files/betaCOMPs_that_.ps}

The grammar handles the following complementizers: that, whether, if, for, and no complementizer, and the clause types: indicative, infinitival, gerundive, past participial, subjunctive and small clause (nom/prep). The <comp> feature in a clausal tree reflects the value of the complementizer if one has adjoined to the clause. The <comp> and <wh> features receive their root node values from the particular complementizer which anchors the tree. The $\beta $COMPs tree adjoins to an S node with the feature <comp>=nil; this feature indicates that the tree does not already have a complementizer adjoined to it.8.7 We ensure that there are no stacked complementizers by requiring the foot node of $\beta $COMPs to have <comp>=nil.
next up previous contents
Next: Case assignment, for and Up: Sentential Subjects and Sentential Previous: Features Required
XTAG Project
1998-09-14