Utilizing Relative Event Time to Enhance Event-Event Temporal Relation Extraction

Event time is one of the most important features for event-event temporal relation extraction. However, explicit event time information in text is sparse. For example, only about 20% of event mentions in TimeBank-Dense have event-time links. In this paper, we propose a joint model for event-event temporal relation classification and an auxiliary task, relative event time prediction, which predicts the event time as real numbers. We adopt a Stack-Propagation framework to incorporate predicted relative event time for temporal relation classification and keep the differentiability. Our experiments on MA-TRES dataset show that our model can significantly improve the RoBERTa-based baseline and achieve state-of-the-art performance. 1