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General LinguisticsHPSG – Head-Driven Phrase Structure Grammar
Alexandr Rosen
Ústav teoretické a komputacní lingvistikyFilozofická fakulta Univerzity Karlovy
27 March 2013
Rosen (FF UK) LTGF 27 March 2013 1 / 60
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Rosen (FF UK) LTGF 27 March 2013 2 / 60
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Reading
HPSG – brief introductions
Levine, R. D. and Meurers W. D. (2005).HPSG – Linguistic Approach, Formal Foundations, and ComputerRealization.In: Keith Brown (ed.): Encyclopedia of Language and Linguistics,2nd edition, Elsevier, Oxford.http://www.ling.ohio-state.edu/~dm/papers/ell2-hpsg.pdf
Adam Przepiórkowski and Anna Kupsc (2006):HPSG for Slavicists. Glossos, 8.http://dach.ipipan.waw.pl/~adamp/Papers/2000-sling2k/
Rosen (FF UK) LTGF 27 March 2013 4 / 60
Reading
HPSG – more extensive introductions
with a stress on formalism and implementation issues:[Richter(2004)]http://milca.sfs.uni-tuebingen.de/A4/Course/PDF/gramandpars.pdf
an HPSG textbook in English[Sag & Wasow(1999)], [Sag et al.(2003)]an HPSG textbook in German[Müller(2007)]http://hpsg.fu-berlin.de/~stefan/Pub/hpsg-lehrbuch.html
Rosen (FF UK) LTGF 27 March 2013 5 / 60
Reading
HPSG – standard references
Pollard & Sag (1987)Information-Based Syntax and Semantics, Volume I,Center for the Study of language and Information, Stanford[Pollard & Sag(1987)]Pollard & Sag (1994)Head-driven Phrase Structure Grammar,Center for the Study of language and Information, Stanford & TheUniversity of Chicago Press,Chicago and London [Pollard & Sag(1994)]HPSG sites:http://hpsg.stanford.edu/http://www.ling.ohio-state.edu/research/hpsg/
Rosen (FF UK) LTGF 27 March 2013 6 / 60
Reading
HPSG – implementations
An overview of implemented formalisms and grammarsfor several linguistic theories, including HPSG:http://hpsg.fu-berlin.de/~stefan/PS/implementations.pdf
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1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Basics
History
1987: first monograph [Pollard & Sag(1987)]1994: standard reference [Pollard & Sag(1994)]Immediate successor to Generalized Phrase Structure Grammar –GPSG [Gazdar et al.(1985)]– head features, unbounded dependencies, ID/LP format for rulesEclectic – inspired also by:
Functional Unification Grammar – FUG [Kay(1983)]– uniform notation for grammar rules, lexicon, representationLexical-Functional Grammar – LFG [Kaplan & Bresnan(1982)]– lexical rulesCategorial Grammar – CG [Ades & Steedman(1982)]– satisfying valency requirementsthe Government and Binding paradigm – GB [Chomsky(1981)]– analyses of various language phenomena
Rosen (FF UK) LTGF 27 March 2013 9 / 60
Basics
Why HPSG?
Precision of analysis, both in grammar and dataIntegration of diverse sources of knowledgeDeclarative grammarConstraint satisfaction systemScaleable, implementable grammarsPsychological plausability
Rosen (FF UK) LTGF 27 March 2013 10 / 60
Basics
Main features 1/2
HPSG grammar is a set of axioms – ‘constraints’The model: typed feature structures,defined in a hierarchy with multiple inheritance,for morphemes, words, phrases, sentences, ...Lexical entries and grammar rulesas constraints on these expressionsConstraints are combined and applied by unificationMost info is stored in lexical entries,HPSG is very much lexicalized – ‘head-driven’
Rosen (FF UK) LTGF 27 March 2013 11 / 60
Basics
Main features 2/2
The concept of sign [de Saussure(1916)]one description to model all properties of words and phrases:
phonology/graphemicsmorphologysyntaxsemanticspragmaticscombinatory (syntagmatic) properties
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wordPHON 〈she〉
SYNSEM
synsem
LOCAL
local
CATEGORY
category
HEAD
[nounCASE nom
]SUBCAT elist
CONTENT
pers-pronoun
INDEX 1
referentialPER 3rdNUM singGEND fem
RESTRICTION eset
CONTEXT
context
BACKGROUND
psoaQUANTS elist
NUCL
[femaleINST 1
]
Basics
A simple sentence as a tree
phrasePHON 〈Molly,sleeps〉SYNSEM ...HD-DTR 1
NONHD-DTRS 〈 2 〉
���
���
HHH
HHH
2
wordPHON 〈Molly〉SYNSEM ...
1
wordPHON 〈sleeps〉SYNSEM ...
Edges just for readability,1 and 2 are just values
of the attributesHD-DTR and NONHD-DTR.HD-DTR and NONHD-DTR
do not represent word order.Word order is determinedby PHON.
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Basics
The same sentence only as a feature structure
phrasePHON 〈Molly,sleeps〉SYNSEM ...
HD-DTR
wordPHON 〈sleeps〉SYNSEM ...
NONHD-DTRS 〈
wordPHON 〈Molly〉SYNSEM ...
〉
Rosen (FF UK) LTGF 27 March 2013 15 / 60
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Head features
Another sentence, with head features
toldV ,past
���
���
HHH
HHH
MollyN,fem,nom,sg
himN,m,acc,sg
thatN,n,acc,sg
Rosen (FF UK) LTGF 27 March 2013 17 / 60
phrasePHON 〈told,him〉
SYNSEM
synsem
HEAD 1
�����
��
HHH
HHHH
wordPHON 〈told〉
SYNSEM
synsem
HEAD 1
[verbVFORM past
]
wordPHON 〈him〉SYNSEM ...
phrasePHON 〈Lucy,told,him,that〉
SYNSEM
synsem
HEAD 1
����
��
HHHH
HH
wordPHON 〈Lucy〉SYNSEM ...
phrasePHON 〈told,him,that〉
SYNSEM
synsem
HEAD 1
�����
HHHH
H
phrasePHON 〈told,him〉
SYNSEM
synsem
HEAD 1
wordPHON 〈that〉SYNSEM ...
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Valency
Arguments represented as complex categoriesin the lexical entry of the head (similar to categorial grammar)
verb VALENCY
swim 〈NP[nom]〉rain 〈NP[it ]〉hate 〈NP[nom], NP[acc]〉look 〈NP[nom], PP[at ]〉give 〈NP[nom], NP[acc], NP[acc]〉give 〈NP[nom], NP[acc], PP[to]〉try 〈NP[nom], VP[inf ]〉persuade 〈NP[nom], NP[acc], VP[inf ]〉say 〈NP[nom], S[that ]〉
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Valency
phrasePHON 〈John,swims〉
SYNSEM
synsemHEAD 1
VAL 〈〉
��
����
HHHH
HH
phrasePHON 〈swims〉
SYNSEM
synsemHEAD 1 verb
VAL 〈 2 〉
wordPHON 〈John〉SYNSEM 2
Rosen (FF UK) LTGF 27 March 2013 22 / 60
Valency
Abbreviations
S phrase
SYNSEM
synsemHEAD verbVAL 〈〉
VP phrase
SYNSEM
synsemHEAD verbVAL 〈sign〉
V word
SYNSEM
synsemHEAD verbVAL list
NP phrase
SYNSEM
synsemHEAD nounVAL 〈〉
Rosen (FF UK) LTGF 27 March 2013 23 / 60
Valency
Valency
Unlike head features, valency can changewith the level of projection.Thus, the list of valency requirementscannot be included in the value of the attribute HEAD.
Lucka Jirkovi nic nerekla‘Lucy didn’t say anything to Jirka.’
Rosen (FF UK) LTGF 27 March 2013 24 / 60
phrasePHON 〈jirkovi,nerekla〉
SYNSEM
synsemHEAD 4
VAL 〈 1 , 2 〉
���
���
HHH
HHH
wordPHON 〈jirkovi〉SYNSEM 3
wordPHON 〈nerekla〉
SYNSEM
synsemHEAD 4
VAL 〈 1 , 2 , 3 〉
phrasePHON 〈jirkovi,nic,nerekla〉
SYNSEM
synsemHEAD 4
VAL 〈 1 〉
��
����
HHH
HHH
phrasePHON 〈jirkovi,nerekla〉
SYNSEM
synsemHEAD 4
VAL 〈 1 , 2 〉
wordPHON 〈nic〉SYNSEM 2
phrasePHON 〈lucka,jirkovi,nic,nerekla〉
SYNSEM
synsemHEAD 4
VAL 〈〉
���
���
HHH
HHH
wordPHON 〈lucka〉SYNSEM 1
phrasePHON 〈jirkovi,nic,nerekla〉
SYNSEM
synsemHEAD 4
VAL 〈 1 〉
Valency
Valency (summary)
The features HEAD and VAL provide informationabout the word’s syntactic word class andthe degree its valency requirements are satisfied.
This information is partially implicit in the standard atomiccategories of CF grammar: N, N’, NP, V, VP, S.These are often used as abbreviations.Often the attribute CATEGORY or CAT groups these two features,serving as the locus of the item’s syntactic information.CAT is just one of synsem’s attributes.Rather than signs, valency lists include synsems. Why?
Rosen (FF UK) LTGF 27 March 2013 28 / 60
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Grammar
The grammar architecture
Components of a grammar:Signature (defines possible objects)Theory (specifies constraints on the objects)
Components of a theory:Lexical entries (word-specific constraints)Lexical rules(expressing lexical generalizations – morphology, alternations)Principles (syntactic regularities)Schemas (relating phonology and syntactic structure)Relational constraints (list operations etc.)
Rosen (FF UK) LTGF 27 March 2013 30 / 60
Grammar
Rules
Abstracting from word order:ID/LP rules (Immediate Dominance vs. Linear Precedence)dominance in DTR, precedence in PHON
Abstracting from word classes:V, N, P, A
A general schema:H [ VALENCY 1 ] −→ H [ VALENCY 1 ⊕ 〈 2 〉] 2
Possible instantiations:V [ VALENCY 1 ] −→ V [ VALENCY 1 〈〉 ⊕ 〈 2 NP〉] 22 John swims. 2 Mary [loves strawberries].
V [ VALENCY 1 ] −→ V [ VALENCY 1 〈NP〉 ⊕ 〈 2 NP〉] 2loves 2 strawberriesN [ VALENCY 1 ] −→ N [ VALENCY 1 〈〉 ⊕ 〈 2 DET〉] 22 [my younger sister’s] boyfriend.
Rosen (FF UK) LTGF 27 March 2013 31 / 60
Grammar
More abstractions
H [ VALENCY 4 ] −→ H [ VALENCY 4 ⊕ 〈 5 〉] 5
phrase→
PHON f ( 1 , 2 )HEAD 3
VALENCY 4
HD-DTR
PHON 1
HEAD 3
VALENCY 4 ⊕ 〈 5 〉
NONHD-DTRS 〈 5
[PHON 2
]〉
The rule schema includes several types of info:
dominanceconcatenation of PHON valuesvalency satisfactionhead features sharing
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Grammar
Principles
Schemaphrase→
PHON f ( 1 , 2 )
HD-DTR[
PHON 1]
NONHD-DTRS 5[
PHON 2]
Head Feature Principlephrase→
HEAD 3
HD-DTR[
HEAD 3]
Valency Principlephrase→
SYNSEM | VALENCY 4
HD-DTR[
VALENCY 4 ⊕ 〈 5 〉]
NONHD-DTRS 5
Rosen (FF UK) LTGF 27 March 2013 33 / 60
Grammar
The type sign (simplified)
signPHON list(phonstring)
SYNSEM
synsem
CAT
cat
HEAD head
VAL list(synsem)
Rosen (FF UK) LTGF 27 March 2013 34 / 60
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Semantics
Semantics
signPHON list(phonstring)
SYNSEM
synsemCAT cat
CONT cont
Rosen (FF UK) LTGF 27 March 2013 36 / 60
Semantics
cont
�����
HHHH
H
psoa
nom-obj
INDEX
indexPERS persNUMB numbGEND gend
RESTR set(psoa)
Rosen (FF UK) LTGF 27 March 2013 37 / 60
Semantics
psoa
����
���
����
HHHH
HHH
HHH
H
giveGIVER indexGIVEN indexRECIPIENT index
[
swimSWIMMER index
] ...
psoa
������
����
��
����
@@@@
PPPP
PPPP
PPPP
[bookINST index
] [blackINST index
] [quicklyINST psoa
] ...
Rosen (FF UK) LTGF 27 March 2013 38 / 60
Lexical entry for dala:
sign
SS
synsem
CAT
cat
HEAD
[verbVFORM past
]VAL 〈NP[nom] 1 [3rd ,sg,fem]
〉, NP[dat] 2 , NP[acc] 3 〉
CONT
giveGIVER 1
GIVEN 3
RECIPIENT 2
Semantics
NP[nom] i [3rd ,sg,fem] :
synsem
CAT
cat
HEAD
[nounCASE nom
]VAL 〈〉
CONT
nom-obj
INDEX i
indexPERS 3rdNUMB sgGEND fem
Rosen (FF UK) LTGF 27 March 2013 40 / 60
Semantics
A reminder: Lexicon is formally a huge disjunction of constraints on thetype word: word → entry1 ∨ entry2 ∨ entry3 ∨ ...
Lexical entry for kniha ‘book’, the value of CONT:
nom-obj
INDEX 1
indexPERS 3rdNUMB sgGEND fem
RESTR
[
bookINST 1
]
Rosen (FF UK) LTGF 27 March 2013 41 / 60
Semantics
NP tlustá kniha ‘a thick book’, the value of CONT:
nom-obj
INDEX 1
indexPERS 3rdNUMB sgGEND fem
RESTR
[
bookINST 1
],
[thickINST 1
]
Rosen (FF UK) LTGF 27 March 2013 42 / 60
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
Unbounded dependencies
Unbounded dependencies:LOCAL/NONLOCAL, filler/gap
S
����
HHHH
NP1dumplings
S/NP1
���
HHH
NPwe
VP/NP1�� HH
Vadore
NP1ε
Rosen (FF UK) LTGF 27 March 2013 44 / 60
Unbounded dependencies
S
����
HHHH
NP1what
S/NP1
����
HHH
H
NPMary
VP/NP1
�� HH
Vadores
NP1ε
Rosen (FF UK) LTGF 27 March 2013 45 / 60
Unbounded dependencies
S
����
HHH
H
NP1who
S/NP1
����
HHHH
NPMary
VP/NP1
���
HHH
Vcan’t
VP/NP1�� HH
Vstand
NP1ε
Rosen (FF UK) LTGF 27 March 2013 46 / 60
Unbounded dependencies
S
����
HHHH
NP1who
S/NP1
����
HHHH
NPLucy
VP/NP1
����
HHHH
Vsaid
S’/NP1
����
HHHH
Mthat
S/NP1
����
HHH
H
NPMary
VP/NP1
���
HHH
Vcan’t
VP/NP1�� HH
Vstand
NP1ε
Rosen (FF UK) LTGF 27 March 2013 47 / 60
phrasePHON list(phonstring)
SS
synsem
LOCAL
local
CAT
catHEAD headVAL list(synsem)
NONLOCAL
[nonlocalSLASH set(local)
]
HD-DTR signNONHD-DTRS list(sign)
Unbounded dependencies
phrase
����
HHHH
val-phrase fill-phrase
Rosen (FF UK) LTGF 27 March 2013 49 / 60
Unbounded dependencies
Filler phrase
fill-phrasePHON 〈dumplings,we,adore〉SYNSEM | NONLOCAL | SLASH{}
HEAD-DTR
val-phrasePHON 〈we,adore〉
SYNSEM | NONLOCAL | SLASH{
1}
NONHD-DTRS
word
PHON 〈dumplings〉SYNSEM | LOCAL 1
Rosen (FF UK) LTGF 27 March 2013 50 / 60
Unbounded dependencies
TracewordPHON 〈〉
SYNSEM
LOCAL 1
NONLOCAL | SLASH{
1}
Rosen (FF UK) LTGF 27 March 2013 51 / 60
fill-phraseP 〈dumplings,we,adore〉..SUBJ 〈〉..COMPS 〈〉..SLASH{}
�����
HHHH
H
wordP 〈dumplings〉..LOCAL 1
val-phraseP 〈we,adore〉
..SUBJ 〈〉..COMPS 〈〉..SLASH{
1}
�����
HHH
HH
wordP 〈we〉SS 3
val-phraseP 〈adore〉
..SUBJ 〈 3 〉..COMPS 〈〉..SLASH{
1}
����
��
HHHH
HH
wordP 〈adore〉..SUBJ 〈 3 〉..COMPS 〈 2 〉..SLASH{}
wordP 〈〉
SS 2
LOCAL 1
..SLASH{
1}
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
wordPHON 〈já〉
SS
synsem
CAT
cat
HEAD
[nounCASE nom
]VAL 〈〉
CONT
nom-obj
INDEX 1
indexPERS 1stNUM sgGEND gend
RESTR{}
CTX
ctx
C-INDS
c-indsSPEAKER 1
ADDRESSEE index
BCKGRND{}
wordPHON 〈vy〉
SS
synsem
CAT
cat
HEAD
[nounCASE nom
]VAL
[SUBJ 〈〉, COMPS 〈〉
]
CONT
nom-obj
INDEX 1
[indexPERS 2nd, NUM pl, GEND gend
]RESTR{}
CTX
ctx
C-INDS
c-indsSPEAKER 2
ADDRESSEE 1
BCKGRND
honor
HONORER 2
HONORED 1
,
[non-aggregINST 1
]
1 Reading
2 Basics
3 Head features
4 Valency
5 Grammar
6 Semantics
7 Unbounded dependencies
8 Pragmatics
9 References
References
Ades, A. E. & Steedman, M. J. (1982).On the order of words.Linguistics and Philosophy, 4, 517–558.10.1007/BF00360804.
Chomsky, N. (1981).Lectures on Government and Binding.Foris, Dordrecht.
Dalrymple, M., Kaplan, R. M., Maxwell, J. T., & Zaenen, A., editors(1995).Formal Issues in Lexical-Functional Grammar.CSLI Publications, Stanford, CA.
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References
de Saussure, F. (1916).Cours de linguistique générale.Paris.Publié par Ch. Bally et A. Sechehay avec la collaboration de ARiedlinger.
Gazdar, G., Klein, E., Pullum, G., & Sag, I. (1985).Generalized phrase structure grammar.Harvard University Press, Cambridge, MA, USA.
Kaplan, R. D. & Bresnan, J. (1982).Lexical-Functional Grammar: A Formal System for GrammaticalRepresentation.In J. Bresnan, editor, The Mental Representation of GrammaticalRelations, pages 173–281. The MIT Press, Cambridge, MA.Reprinted in [Dalrymple et al.(1995), 29-130].
Rosen (FF UK) LTGF 27 March 2013 58 / 60
References
Kay, M. (1983).Unification Grammar.Technical report, Xerox Palo Alto Research Center, Palo Alto,California.
Müller, S. (2007).Head-Driven Phrase Structure Grammar: Eine Einführung.Number 17 in Stauffenburg Einführungen. Staffenburg Verlag,Tübingen.
Pollard, C. & Sag, I. A. (1994).Head-Driven Phrase Structure Grammar.University of Chicago Press.
Pollard, C. J. & Sag, I. A. (1987).Information-Based Syntax and Semantics.Number 13 in CSLI Lecture Notes. CSLI, Stanford, California, USA.
Rosen (FF UK) LTGF 27 March 2013 59 / 60
References
Richter, F. (2004).A Web-based Course in Grammar Formalisms and Parsing.An electronic course book,http://milca.sfs.uni-tuebingen.de/A4/Course/PDF/gramandpars.pdf.
Sag, I. A. & Wasow, T. (1999).Syntactic Theory: A Formal Introduction.CSLI Publications, Stanford, CA.
Sag, I. A., Wasow, T., & Bender, E. M. (2003).Syntactic Theory: A Formal Introduction.CSLI Publications, Stanford, CA, 2 edition.
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