Dependency Parsing Schemata and Mildly Non-Projective Dependency Parsing

Gómez-Rodríguez, Carlos; Carroll, John; Weir, David

doi:10.1162/coli_a_00060

Cited by 32 publications

(37 citation statements)

References 31 publications

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“…However, while some classes of dependency structures tolerating certain crossings have a very good empirical coverage [31,[42][43][44], these proposals still face counterexamples that fall outside the restrictions [45][46][47].…”

Section: A Minimization Of Crossingsmentioning

confidence: 99%

Scarcity of crossing dependencies: A direct outcome of a specific constraint?

Gómez-Rodríguez

Ferrer-i-Cancho

2017

Phys. Rev. E

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The structure of a sentence can be represented as a network where vertices are words and edges indicate syntactic dependencies. Interestingly, crossing syntactic dependencies have been observed to be infrequent in human languages. This leads to the question of whether the scarcity of crossings in languages arises from an independent and specific constraint on crossings. We provide statistical evidence suggesting that this is not the case, as the proportion of dependency crossings of sentences from a wide range of languages can be accurately estimated by a simple predictor based on a null hypothesis on the local probability that two dependencies cross given their lengths. The relative error of this predictor never exceeds 5% on average, whereas the error of a baseline predictor assuming a random ordering of the words of a sentence is at least 6 times greater. Our results suggest that the low frequency of crossings in natural languages is neither originated by hidden knowledge of language nor by the undesirability of crossings per se, but as a mere side effect of the principle of dependency length minimization.

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Section: A Minimization Of Crossingsmentioning

confidence: 99%

Scarcity of crossing dependencies: A direct outcome of a specific constraint?

Gómez-Rodríguez

Ferrer-i-Cancho

2017

Phys. Rev. E

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“…A dynamic programming algorithm has been proposed for parsing well-nested and k-bounded block degree dependency trees in (Gómez-Rodríguez et al, 2009;Gómez-Rodríguez et al, 2011). Unfortunately, it has a prohibitive O(n 3+2k ) time complexity, equivalent to Lexicalized TAG parsing when k = 2.…”

Section: Related Workmentioning

confidence: 99%

Dependency Parsing with Bounded Block Degree and Well-nestedness via Lagrangian Relaxation and Branch-and-Bound

Corro

Roux

Lacroix

et al. 2016

Proceedings of the 54th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

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We present a novel dependency parsing method which enforces two structural properties on dependency trees: bounded block degree and well-nestedness. These properties are useful to better represent the set of admissible dependency structures in treebanks and connect dependency parsing to context-sensitive grammatical formalisms. We cast this problem as an Integer Linear Program that we solve with Lagrangian Relaxation from which we derive a heuristic and an exact method based on a Branch-and-Bound search. Experimentally, we see that these methods are efficient and competitive compared to a baseline unconstrained parser, while enforcing structural properties in all cases.

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“…Many interesting semiring computations on the original grammar can be simulated on the binarized grammar, however. A direct parsing algorithm for wellnested dependency trees has been presented by Gómez-Rodríguez, Carroll, and Weir (2011). The binarization that we present here is a special case of the binarization proposed by Gómez-Rodríguez, Kuhlmann, and Satta (2010).…”

Section: Lemma 10mentioning

confidence: 99%

Mildly Non-Projective Dependency Grammar

Kuhlmann

2013

Computational Linguistics

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Syntactic representations based on word-to-word dependencies have a long-standing tradition in descriptive linguistics, and receive considerable interest in many applications. Nevertheless, dependency syntax has remained somewhat of an island from a formal point of view. Moreover, most formalisms available for dependency grammar are restricted to projective analyses, and thus not able to support natural accounts of phenomena such as wh-movement and cross–serial dependencies. In this article we present a formalism for non-projective dependency grammar in the framework of linear context-free rewriting systems. A characteristic property of our formalism is a close correspondence between the non-projectivity of the dependency trees admitted by a grammar on the one hand, and the parsing complexity of the grammar on the other. We show that parsing with unrestricted grammars is intractable. We therefore study two constraints on non-projectivity, block-degree and well-nestedness. Jointly, these two constraints define a class of “mildly” non-projective dependency grammars that can be parsed in polynomial time. An evaluation on five dependency treebanks shows that these grammars have a good coverage on empirical data

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Dependency Parsing Schemata and Mildly Non-Projective Dependency Parsing

Cited by 32 publications

References 31 publications

Scarcity of crossing dependencies: A direct outcome of a specific constraint?

Scarcity of crossing dependencies: A direct outcome of a specific constraint?

Dependency Parsing with Bounded Block Degree and Well-nestedness via Lagrangian Relaxation and Branch-and-Bound

Mildly Non-Projective Dependency Grammar

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