PRover: Proof Generation for Interpretable Reasoning over Rules

Swarnadeep Saha, Sayan Ghosh, Shashank Srivastava, Mohit Bansal


Abstract
Recent work by Clark et al. (2020) shows that transformers can act as “soft theorem provers” by answering questions over explicitly provided knowledge in natural language. In our work, we take a step closer to emulating formal theorem provers, by proposing PRover, an interpretable transformer-based model that jointly answers binary questions over rule-bases and generates the corresponding proofs. Our model learns to predict nodes and edges corresponding to proof graphs in an efficient constrained training paradigm. During inference, a valid proof, satisfying a set of global constraints is generated. We conduct experiments on synthetic, hand-authored, and human-paraphrased rule-bases to show promising results for QA and proof generation, with strong generalization performance. First, PRover generates proofs with an accuracy of 87%, while retaining or improving performance on the QA task, compared to RuleTakers (up to 6% improvement on zero-shot evaluation). Second, when trained on questions requiring lower depths of reasoning, it generalizes significantly better to higher depths (up to 15% improvement). Third, PRover obtains near perfect QA accuracy of 98% using only 40% of the training data. However, generating proofs for questions requiring higher depths of reasoning becomes challenging, and the accuracy drops to 65% for “depth 5”, indicating significant scope for future work.
Anthology ID:
2020.emnlp-main.9
Volume:
Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP)
Month:
November
Year:
2020
Address:
Online
Editors:
Bonnie Webber, Trevor Cohn, Yulan He, Yang Liu
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
122–136
Language:
URL:
https://aclanthology.org/2020.emnlp-main.9
DOI:
10.18653/v1/2020.emnlp-main.9
Bibkey:
Cite (ACL):
Swarnadeep Saha, Sayan Ghosh, Shashank Srivastava, and Mohit Bansal. 2020. PRover: Proof Generation for Interpretable Reasoning over Rules. In Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP), pages 122–136, Online. Association for Computational Linguistics.
Cite (Informal):
PRover: Proof Generation for Interpretable Reasoning over Rules (Saha et al., EMNLP 2020)
Copy Citation:
PDF:
https://aclanthology.org/2020.emnlp-main.9.pdf
Video:
 https://slideslive.com/38939033
Code
 swarnaHub/PRover +  additional community code