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neg,
possible values are +, -
Used for controlling the interaction of negation and auxiliary verbs.
pred,
possible values are +, -
The pred
feature is used in the following tree
families: Tnx0N1.trees and Tnx0nx1ARB.trees.
In the Tnx0N1.trees family, the following equations are used:
for W1nx0N1:
(621)0(621
- (622)
- NP1.t:pred
= +
(622)0(622
- (623)
- NP1.b:pred
= +
(623)0(623
- (624)
- NP.t:pred
= +
(624)0(624
- (625)
- N.t:pred
= NP.b:pred
This is the only tree in this tree family to use the pred
feature.
The other tree family where the pred
feature is
used is Tnx0nx1ARB.trees. Within this family, this feature (and the
following equations) are used only in the W1nx0nx1ARB tree.
(625)0(625
- (626)
- AdvP1.t:pred
= +
(626)0(626
- (627)
- AdvP1.b:pred
= +
(627)0(627
- (628)
- NP.t:pred
= +
(628)0(628
- (629)
- AdvP.b:pred
= NP.t:pred
pron,
possible values are +, -
This feature indicates whether a particular NP is a pronoun or not.
Certain constructions which do not permit pronouns use this
feature to block pronouns.
tense,
possible values are pres, past
It does not seem to be the case that the tense
feature interacts with other features/syntactic processes. It
comes from the lexicon with the verb and is transmitted up the
tree in such a way that the root S node ends up with the
tense feature of the highest verb in the tree. The equations
used for this purpose are:
(629)0(629
- (630)
- Sr.b:tense = VP.t:tense
(630)0(630
- (631)
- VP.b:tense = V.t:tense
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Previous: Control
XTAG Project
http://www.cis.upenn.edu/~xtag