Free the Plural: Unrestricted Split-Antecedent Anaphora Resolution

Juntao Yu, Nafise Sadat Moosavi, Silviu Paun, Massimo Poesio


Abstract
Now that the performance of coreference resolvers on the simpler forms of anaphoric reference has greatly improved, more attention is devoted to more complex aspects of anaphora. One limitation of virtually all coreference resolution models is the focus on single-antecedent anaphors. Plural anaphors with multiple antecedents-so-called split-antecedent anaphors (as in John met Mary. They went to the movies) have not been widely studied, because they are not annotated in ONTONOTES and are relatively infrequent in other corpora. In this paper, we introduce the first model for unrestricted resolution of split-antecedent anaphors. We start with a strong baseline enhanced by BERT embeddings, and show that we can substantially improve its performance by addressing the sparsity issue. To do this, we experiment with auxiliary corpora where split-antecedent anaphors were annotated by the crowd, and with transfer learning models using element-of bridging references and single-antecedent coreference as auxiliary tasks. Evaluation on the gold annotated ARRAU corpus shows that the out best model uses a combination of three auxiliary corpora achieved F1 scores of 70% and 43.6% when evaluated in a lenient and strict setting, respectively, i.e., 11 and 21 percentage points gain when compared with our baseline.
Anthology ID:
2020.coling-main.538
Volume:
Proceedings of the 28th International Conference on Computational Linguistics
Month:
December
Year:
2020
Address:
Barcelona, Spain (Online)
Editors:
Donia Scott, Nuria Bel, Chengqing Zong
Venue:
COLING
SIG:
Publisher:
International Committee on Computational Linguistics
Note:
Pages:
6113–6125
Language:
URL:
https://aclanthology.org/2020.coling-main.538
DOI:
10.18653/v1/2020.coling-main.538
Bibkey:
Cite (ACL):
Juntao Yu, Nafise Sadat Moosavi, Silviu Paun, and Massimo Poesio. 2020. Free the Plural: Unrestricted Split-Antecedent Anaphora Resolution. In Proceedings of the 28th International Conference on Computational Linguistics, pages 6113–6125, Barcelona, Spain (Online). International Committee on Computational Linguistics.
Cite (Informal):
Free the Plural: Unrestricted Split-Antecedent Anaphora Resolution (Yu et al., COLING 2020)
Copy Citation:
PDF:
https://aclanthology.org/2020.coling-main.538.pdf
Video:
 https://slideslive.com/38940702
Code
 juntaoy/dali-plural
Data
WikiCREM