Notes on computational linguistics.pdf - UCLA Department of ...

Stabler - Lx 185/209 2003
T
t
C
C
CP
C’
DP(0)
D
the
D’
NP
N’
N
student
TP
T
t
DP
D’
D
T’
V
try
vP
v
v
v
T
-s
v’
V
t
T
to
VP
V’
TP
T’
DP
t(0)
V
laugh
vP
v
v’
v
VP
V’
V
t
([],[],the student try -s to laugh):C
[]::=>T C (the student,[],try -s to laugh):T
([],[],try -s to laugh):+k T,([],the,student):-k
-s::v==> +k T ([],try,to laugh):v,([],the,student):-k
([],try,to laugh):=D v
[]::D
[]::=>V =D v ([],try,to laugh):V,([],the,student):-k
try::=T V ([],to,laugh):T,([],the,student):-k
to::=v T ([],laugh,[]):v,([],the,student):-k
([],laugh,[]):=D v
[]::=>V =D v laugh::V
([],the,student):D -k
the::=N D -k student::N
This second derivation is kind of wierd – it does not correspond to the semantic relations we wanted. How can
we rule it out?
One idea is that this empty pronoun (sometimes called PRO) actually requires some kind of feature checking
relation with the infinitive tense. Sometimes the relevant feature is called “null case” (Chomsky and Lasnik,
1993; Watanabe, 1993; Martin, 1996). (In fact, the proper account of control constructions is still controversial
– cf., for example, Hornstein, 1999.)
A simple version of this proposal is to use a new feature k0 for “null case,” in lexical items like these:
ɛ:: D -k0
to::=v +k0 T to::=Have +k0 T to::=Be +k0 T
With these we derive just one analysis for the student try -s to laugh:
T
t
C
C
CP
C’
DP(1)
D
the
D’
NP
N’
N
student
TP
T
t
T’
DP
t(1)
V
try
v
v
vP
v
T
-s
v’
V
t
VP
V’
DP(0)
D’
D
TP
T
to
T’
DP
t(0)
V
laugh
vP
v
v’
v
VP
V’
V
t
([],[],the student try -s to laugh):C
[]::=>T C (the student,[],try -s to laugh):T
([],[],try -s to laugh):+k T,([],the,student):-k
-s::v==> +k T ([],try,to laugh):v,([],the,student):-k
([],try,to laugh):=D v
[]::=>V =D v ([],try,to laugh):V
try::=T V ([],to,laugh):T
([],to,laugh):+k0 T,([],[],[]):-k0
to::=v +k0 T ([],laugh,[]):v,([],[],[]):-k0
([],laugh,[]):=D v
[]::=>V =D v laugh::V
Notice how this corresponds to the semantic relations diagrammed on the previous page.
219
([],the,student):D -k
the::=N D -k student::N
[]::D -k0