Lexical Functional Grammar

1
Lexical Functional Grammar

• 11-722 Grammar Formalisms
• Spring Term 2004

2
SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

S
NP VP
N V VP-bar
COMP VP
V PP
P NP
DET N
Lions seem to live in the forest
3
SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

f1
f2
S
n1
f3
NP VP
n4
n2
N V VP-bar
n5
n3
n6
f4
COMP VP
n7
n8
f5
f6
V PP
n10
n9
P NP
n12
n11
DET N
n13
n14
Lions seem to live in the forest
4
SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

f1
f2
S
n1
f3
NP VP
n4
n2
N V VP-bar
n5
n3
n6
f4
COMP VP
n7
n8
f5
f6
V PP
n10
n9
P NP
n12
n11
DET N
n13
n14
Lions seem to live in the forest
5
Properties of the mapping from c-structure to
f-structure

• Each c-structure node maps onto at most one
  f-structure node.
• More than one c-structure node can map onto the
  same f-structure node.
• An f-structure node does not have to correspond
  to any c-structure node. (But the information it
  contains does come from somewhere either a
  grammar rule or lexical entry.)

6
The formalism for grammatical encoding Local
co-description of partial structures

• F is a mapping from c-structure nodes to
  f-structure nodes.
• There are other mappings to semantic structures,
  argument structures, discourse structures,etc.
• is the current c-structure node (me).
• F() is my f-structure (?)
• m() is my c-structure mother
• F(m()) is my c-structure mothers f-structure
  (?)

7
Local co-description of partial structures

• S ? NP VP
• (? SUBJ) ? ? ?
• NP says My mothers f-structure has a SUBJ
  feature whose value is my f-structure.
• VP says My mothers f-structure is my
  f-structure.
• This rule simultaneously describes a piece of
  c-structure and a piece of f-structure.
• It is local because each equation refers only to
  the current node and its mother. (page 119-120)

8
Other types of equations

• F-structure composition
• (? SUBJ NUM) sg
• My f-structure has a subj feature, whose value is
  another f-structure, which has a num feature,
  whose value is sg.
• Usually, path names are not longer than two.
• Two features pointing to the same value
• (? SUBJ) (? XCOMP SUBJ)
• (? SUBJ) (? TOPIC)
• (? (? CASE)) ? (Dalrymple pages 152-153)
• Sam walked in the park.
• (? CASE) OBL-loc
• (? OBL-loc) ?

9
The minimal solution

• The f-structure for a sentence is the minimal
  f-structure that satisfies all of the equations.
  (page 101).

10
Building an F-structure informal, for linguists

• Annotate
• Assign a variable name to the f-structure
  corresponding to each c-structure node.
• May find out later that some of them are the
  same.
• Instantiate
• Replace the arrows with the variable names.
• Solve
• Locate the f-structure named on the left side of
  the equation.
• Locate the f-structure named on the right side of
  the equation
• Unify them.
• Replace both of them with the result of
  unification.

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Rule S ? NP VP (?
SUBJ) ? ??
(?VFORM) fin Instantiated equations (f1
SUBJ) f2 f1 f3
SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

f2
f1
f3
S f1
NP f2 VP f3
N V VP-bar
COMP VP
V PP
P NP
DET N
Lions seem to live in the forest
12
Equivalent to drawing f-structures on nodes as in
TAG
S 1VFORM fin
NP VP 1 SUBJ 2
1
13
lion N seem V (? PRED)
lion (? PRED)
seem lt theme gt
SUBJ
XCOMP
(? SUBJ)
(? XCOMP SUBJ) -s (suffix
for nouns) (? NUM) pl - Ø (suffix
for verbs) (? PERS) 3 (? VFORM)
fin (? SUBJ
NUM) pl
SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

f4
S
NP VP
f5
f4 N f5 V VP-bar
COMP VP
V PP
P NP
DET N
Lions seem to live in the forest
14
lion N seem V (f4
PRED) lion (f5 PRED)
seem lt
theme gt SUBJ
XCOMP
(f5 SUBJ)
(f5 XCOMP SUBJ) -s
(suffix for nouns) (f4 NUM) pl -
Ø (suffix for verbs) (f4 PERS) 3
(f5 VFORM) fin
(f5 SUBJ NUM) pl
SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

f4
S
NP VP
f5
f4 N f5 V VP-bar
COMP VP
V PP
P NP
DET N
Lions seem to live in the forest
15
What is an XCOMP

• A non-finite clause, predicate nominal, predicate
  adjective, or predicate PP
• Sam seemed to be happy (VP)
• Sam seemed happy (AP)
• Sam became a teacher (NP)
• We had them arrested (VP)
• We kept them in the drawer (PP)
• Has to be an argument of a verb
• Arrested by the police, Sam had no alternative
  but to give up his life of crime.
• This is an adjunct, not an XCOMP
• Gets its subject by sharing with another verb
• I think that Sam is happy.
• This is a COMP, not an XCOMP

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seem V (? PRED) seem lt theme gt SUBJ
XCOMP (? SUBJ) (?
XCOMP SUBJ) (? XCOMP VFORM)
INF - Ø (suffix for verbs) (? VFORM) fin (?
SUBJ NUM) pl
VP ? V VP ?? (? XCOMP) ?

SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

f3
S
f5
NP VP f3
f6
f7
N f5 V f8 VP-bar
f8
f6COMP VP f9
f9
f7V PP
P NP
to COMP - Ø (suffix
for verbs) (? VFORM) INF (?
VFORM) INF live V (? PRED) livelttheme
locgt SUBJ OBL
DET N
Lions seem to live in the forest
17
seem V (f5 PRED) seem lt theme gt SUBJ
XCOMP (f5 SUBJ)
(f5 XCOMP SUBJ) (f5 XCOMP
VFORM) INF - Ø (suffix for verbs) (f5 VFORM)
fin (f5 SUBJ NUM) pl
VP ? V VP f3f5
(f3 XCOMP) f8
SUBJ PRED lion
NUM pl
PERS 3 PRED seem lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

f3
S
f5
NP VP f3
f6
f7
N f5 V f8 VP-bar
f8
f6COMP VP f9
f9
f7V PP
P NP
to COMP - Ø (suffix
for verbs) (f6 VFORM) INF (f7
VFORM) INF live V (f7 PRED) livelttheme
locgt SUBJ OBL
DET N
Lions seem to live in the forest
18
SUBJ PRED lion
NUM pl
PERS 3 PRED try lt
agent theme gt
SUBJ XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM INF
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

S
NP VP
N V VP-bar
COMP VP
V PP
P NP
DET N
Lions try to live in the forest
19
have V (? PRED) have lt theme gt SUBJ
XCOMP (? SUBJ) (?
XCOMP SUBJ) (? XCOMP VFORM)
PASTPART - Ø (suffix for verbs) (? VFORM) fin
(? SUBJ NUM) pl
SUBJ PRED lion
NUM pl
PERS 3 PRED have lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM PASTPART
PRED livelt theme loc gt
SUBJ
OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

S
NP VP
N V
VP
V PP
P NP
DET N
Lions have lived in the forest
20
were V (? PRED) be lt theme gt SUBJ
XCOMP (? SUBJ) (? XCOMP
SUBJ) (? XCOMP VFORM)
PASSIVE (? VFORM) fin (? SUBJ NUM) pl
SUBJ PRED lion
NUM pl
PERS 3 PRED be lt
theme gt SUBJ
XCOMP TENSE pres VFORM
fin XCOMP SUBJ
VFORM PASSIVE
PRED huntltagent theme loc gt
Ø
SUBJ OBL-loc OBJ
OBL-loc CASE OBL-loc
PRED
inltOBJgt
OBJ PRED forest

NUM sg

PERS 3
DEF

S
NP VP
N V
VP
V PP
P NP
DET N
Lions were hunted in the forest