Before revision:  In addition , we describe the proposed methods by analyzing the technical perspectives of the different approaches and discussing the performance results on the FEVER dataset  .
After revision:  In addition , we describe the proposed methods by analyzing the technical perspectives of the different approaches and discussing the performance results on the FEVER dataset , which is the most well-studied and formally structured dataset on the fact extraction and verification task. We also conduct the largest experimental study to date on identifying beneficial loss functions for the sentence retrieval component. Our analysis indicates that sampling negative sentences is important for improving the performance and decreasing the computational complexity. Finally, we describe open issues and future challenges, and we motivate future research in the task .