Constituency Parsing

73 papers with code • 4 benchmarks • 6 datasets

Constituency parsing aims to extract a constituency-based parse tree from a sentence that represents its syntactic structure according to a phrase structure grammar.

Example:

             Sentence (S)
                 |
   +-------------+------------+
   |                          |
 Noun (N)                Verb Phrase (VP)
   |                          |
 John                 +-------+--------+
                      |                |
                    Verb (V)         Noun (N)
                      |                |
                    sees              Bill

Recent approaches convert the parse tree into a sequence following a depth-first traversal in order to be able to apply sequence-to-sequence models to it. The linearized version of the above parse tree looks as follows: (S (N) (VP V N)).

Most implemented papers

Tetra-Tagging: Word-Synchronous Parsing with Linear-Time Inference

nikitakit/tetra-tagging ACL 2020

We present a constituency parsing algorithm that, like a supertagger, works by assigning labels to each word in a sentence.

Rethinking Self-Attention: Towards Interpretability in Neural Parsing

KhalilMrini/LAL-Parser Findings of the Association for Computational Linguistics 2020

Finally, we find that the Label Attention heads learn relations between syntactic categories and show pathways to analyze errors.

Fast and Accurate Neural CRF Constituency Parsing

yzhangcs/crfpar IJCAI 2020

Estimating probability distribution is one of the core issues in the NLP field.

StructFormer: Joint Unsupervised Induction of Dependency and Constituency Structure from Masked Language Modeling

google-research/google-research ACL 2021

There are two major classes of natural language grammar -- the dependency grammar that models one-to-one correspondences between words and the constituency grammar that models the assembly of one or several corresponded words.

Grammar-Constrained Decoding for Structured NLP Tasks without Finetuning

epfl-dlab/gcd 23 May 2023

In this work, we demonstrate that formal grammars can describe the output space for a much wider range of tasks and argue that GCD can serve as a unified framework for structured NLP tasks in general.

Effective Self-Training for Parsing

BLLIP/bllip-parser NAACL 2006

We present a simple, but surprisingly effective, method of self-training a two-phase parser-reranker system using readily available unlabeled data.