A Semi-Autoregressive Graph Generative Model for Dependency Graph Parsing

Ye Ma, Mingming Sun, Ping Li


Abstract
Recent years have witnessed the impressive progress in Neural Dependency Parsing. According to the different factorization approaches to the graph joint probabilities, existing parsers can be roughly divided into autoregressive and non-autoregressive patterns. The former means that the graph should be factorized into multiple sequentially dependent components, then it can be built up component by component. And the latter assumes these components to be independent so that they can be outputted in a one-shot manner. However, when treating the directed edge as an explicit dependency relationship, we discover that there is a mixture of independent and interdependent components in the dependency graph, signifying that both aforementioned models fail to precisely capture the explicit dependencies among nodes and edges. Based on this property, we design a Semi-Autoregressive Dependency Parser to generate dependency graphs via adding node groups and edge groups autoregressively while pouring out all group elements in parallel. The model gains a trade-off between non-autoregression and autoregression, which respectively suffer from the lack of target inter-dependencies and the uncertainty of graph generation orders. The experiments show the proposed parser outperforms strong baselines on Enhanced Universal Dependencies of multiple languages, especially achieving 4% average promotion at graph-level accuracy. Also, the performances of model variations show the importance of specific parts.
Anthology ID:
2023.findings-acl.259
Volume:
Findings of the Association for Computational Linguistics: ACL 2023
Month:
July
Year:
2023
Address:
Toronto, Canada
Editors:
Anna Rogers, Jordan Boyd-Graber, Naoaki Okazaki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4218–4230
Language:
URL:
https://aclanthology.org/2023.findings-acl.259
DOI:
10.18653/v1/2023.findings-acl.259
Bibkey:
Cite (ACL):
Ye Ma, Mingming Sun, and Ping Li. 2023. A Semi-Autoregressive Graph Generative Model for Dependency Graph Parsing. In Findings of the Association for Computational Linguistics: ACL 2023, pages 4218–4230, Toronto, Canada. Association for Computational Linguistics.
Cite (Informal):
A Semi-Autoregressive Graph Generative Model for Dependency Graph Parsing (Ma et al., Findings 2023)
Copy Citation:
PDF:
https://aclanthology.org/2023.findings-acl.259.pdf