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Lexical Functional Grammar

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  1. Lexical Functional Grammar 11-722: Grammar Formalisms Spring Term 2004

  2. SUBJ PRED ‘lion’ NUM pl PERS 3 PRED ‘seem < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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 < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ OBJ PRED ‘forest’ NUM sg PERS 3 DEF + f1 f2 S n1 f3 n2 NP VP n4 n3 N V VP-bar n5 n6 f4 n7 COMP VP 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 < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ OBJ PRED ‘forest’ NUM sg PERS 3 DEF + f1 f2 S n1 f3 n2 NP VP n4 n3 N V VP-bar n5 n6 f4 n7 COMP VP 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 • Φ 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). • Φ(*) is “my f-structure” () • m(*) is “my c-structure mother” • Φ(m(*)) is “my c-structure mother’s f-structure” ()

  7. Local co-description of partial structures • S  NP VP ( SUBJ) =  =  NP says: My mother’s f-structure has a SUBJ feature whose value is my f-structure. VP says: My mother’s 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.

  11. Rule: S → NP VP (↑ SUBJ) = ↓ ↑=↓ (↑VFORM) = fin Instantiated equations: (f1 SUBJ) = f2 f1 = f3 SUBJ PRED ‘lion’ NUM pl PERS 3 PRED ‘seem < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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 [1][VFORM fin] NP VP [1] [SUBJ [2]] [1]

  13. lion: N seem: V (↑ PRED) = `lion’ (↑ PRED) = ‘seem< theme > 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 < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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< theme > 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 < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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

  16. seem: V (↑ PRED) =‘seem< theme > 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 < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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) = `live<theme loc>’ SUBJ OBL DET N Lions seem to live in the forest

  17. seem: V (f5 PRED) =‘seem< theme > 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 f3=f5 (f3 XCOMP) = f8 SUBJ PRED ‘lion’ NUM pl PERS 3 PRED ‘seem < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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) = `live<theme loc>’ SUBJ OBL DET N Lions seem to live in the forest

  18. SUBJ PRED ‘lion’ NUM pl PERS 3 PRED ‘try < agent theme >’ SUBJ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM INF PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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< theme > 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 < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM PASTPART PRED ‘live< theme loc >’ SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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< theme > SUBJ’ XCOMP (↑ SUBJ) = (↑ XCOMP SUBJ) (↑ XCOMP VFORM) = PASSIVE (↑ VFORM) = fin (↑ SUBJ NUM) = pl SUBJ PRED ‘lion’ NUM pl PERS 3 PRED ‘be < theme > SUBJ’ XCOMP TENSE pres VFORM fin XCOMP SUBJ [ ] VFORM PASSIVE PRED ‘hunt<agent theme loc >’ Ø SUBJ OBL-loc OBJ OBL-loc CASE OBL-loc PRED ‘in<OBJ>’ 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