Title
Mildly non-projective dependency structures
Abstract
Syntactic parsing requires a fine balance between expressivity and complexity, so that naturally occurring structures can be accurately parsed without compromising efficiency. In dependency-based parsing, several constraints have been proposed that restrict the class of permissible structures, such as projectivity, planarity, multi-planarity, well-nestedness, gap degree, and edge degree. While projectivity is generally taken to be too restrictive for natural language syntax, it is not clear which of the other proposals strikes the best balance between expressivity and complexity. In this paper, we review and compare the different constraints theoretically, and provide an experimental evaluation using data from two treebanks, investigating how large a proportion of the structures found in the treebanks are permitted under different constraints. The results indicate that a combination of the well-nestedness constraint and a parametric constraint on discontinuity gives a very good fit with the linguistic data.
Year
Venue
Keywords
2006
ACL
non-projective dependency structure,different constraints theoretically,fine balance,best balance,parametric constraint,edge degree,gap degree,dependency-based parsing,linguistic data,different constraint,syntactic parsing,natural language,computer science
Field
DocType
Volume
Computer science,Discontinuity (linguistics),Theoretical computer science,Artificial intelligence,Natural language processing,Syntax,Projective test,Planarity testing,Algorithm,Natural language,Parametric statistics,Parsing,Machine learning,restrict
Conference
P06-2
Citations 
PageRank 
References 
30
1.94
15
Authors
2
Name
Order
Citations
PageRank
Marco Kuhlmann130923.06
Joakim Nivre23652229.07