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Publié par
Nombre de lectures
35
Publié par
Nombre de lectures
35
Introduction
Ralph Debusmann
and
Denys Duchier
Programming Systems Lab, Saarland University, Saarbruc¤ ken, Germany
and
·
Equipe Calligramme, LORIA, Lille, France
A Comparative Introduction to XDG: Introduction ? p.1Purpose of this course
a methodology for modeling language (XDG)
constraint-based (model theoretic syntax)
dependency-based
multiple dimensions
lexicalized
principles governing well-formedness and interactions
macroscopic phenomena are emergent
how to cook your own DG formalism (XDK)
relate techniques and architectural principles to what can be
found elsewhere
A Comparative Introduction to XDG: Introduction ? p.2obj
The notion of a dependency structure
head/dependent asymmetry
named relation
Peter reads a book
A Comparative Introduction to XDG: Introduction ? p.3
subj
detsubj
vzu
vpast
Non-projective analyses
languages with free(r) word-order
crossing branches (non-projectivity)
discontinous constituents
den Roman hat mir Peter versprochen zu lesen
A Comparative Introduction to XDG: Introduction ? p.4
obj
det
iobj
zusubj
vzu
vpast
Model-theoretical view
tree with edges labeled with grammatical relations
must satisfy lexically assigned subcat frames
must satisfy edge-speci c agreement restrictions
den Roman hat mir Peter versprochen zu lesen
A Comparative Introduction to XDG: Introduction ? p.5
obj
det
iobj
zusubj
vzu
vpast
Constraint view
this is a constraint satisfaction problem
given n nodes: nitely many labeled trees
pick one, check the constraints
den Roman hat mir Peter versprochen zu lesen
A Comparative Introduction to XDG: Introduction ? p.6
obj
det
iobj
zusubj
vzu
vpast
Constraint propagation technique
non-deterministic generate and test is inef cient
use constraint propagation to prune the search space
den Roman hat mir Peter versprochen zu lesen
A Comparative Introduction to XDG: Introduction ? p.7
obj
det
iobj
zumf
mf
vcf
xf
Word-order
den hat lesen mir Peter Roman versprochen zu
tradition of German descriptive syntax: topological elds
[den Roman] [hat] [mir Peter] [versprochen] [zu lesen]
VF V2 MF VC NF
idea: topological structure as a dependency tree
den Roman hat mir Peter versprochen zu lesen
A Comparative Introduction to XDG: Introduction ? p.8
df
vf
p
rfsubj
mf
mf
vzu
vcf
vpast
xf
Topological dependency grammar (TDG)
emancipation
den Roman hat mir Peter versprochen zu lesen den Roman hat mir Peter versprochen zu lesen
syntax topology
a TDG analysis has 2 dimensions
tree of syntactic dependencies (non-ordered)
tree of topological dependencies (ordered & projective)
A Comparative Introduction to XDG: Introduction ? p.9
obj
det
df
vf
iobj
p
rf
zusubj
mf
mf
vzu
vcf
vpast
xf
Topological dependency grammar (TDG)
emancipation
den Roman hat mir Peter versprochen zu lesen den Roman hat mir Peter versprochen zu lesen
syntax topology
dimensions are not independent
coupled by the lexicon:
syntax: assignment of a subcat frame
topology: assignment of a topological frame
coupled by a relation of emancipation
syntax and topology are mutually constraining
A Comparative Introduction to XDG: Introduction ? p.10
obj
det
df
vf
iobj
p
rf
zu