The Complexity of Recognition of Linguistically Adequate Dependency Grammars

TL;DR

This paper demonstrates that recognizing linguistically adequate dependency grammars is NP-complete, extending complexity results from phrase structure to dependency frameworks and highlighting computational challenges in dependency parsing.

Contribution

It adapts existing complexity results to dependency grammars, proving NP-completeness for recognition of linguistically adequate dependency grammars, a novel extension in the field.

Findings

Recognition of linguistically adequate dependency grammars is NP-complete.

Extends complexity results from phrase structure to dependency frameworks.

Highlights computational difficulty in dependency parsing.

Abstract

Results of computational complexity exist for a wide range of phrase structure-based grammar formalisms, while there is an apparent lack of such results for dependency-based formalisms. We here adapt a result on the complexity of ID/LP-grammars to the dependency framework. Contrary to previous studies on heavily restricted dependency grammars, we prove that recognition (and thus, parsing) of linguistically adequate dependency grammars is NP-complete.