PermuteFormer: Efficient Relative Position Encoding for Long Sequences Peng Chen author 2021-11 text Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing Marie-Francine Moens editor Xuanjing Huang editor Lucia Specia editor Scott Wen-tau Yih editor Association for Computational Linguistics Online and Punta Cana, Dominican Republic conference publication chen-2021-permuteformer 10.18653/v1/2021.emnlp-main.828 https://aclanthology.org/2021.emnlp-main.828/ 2021-11 10606 10618