RNNs can generate bounded hierarchical languages with optimal memory John Hewitt author Michael Hahn author Surya Ganguli author Percy Liang author Christopher D Manning author 2020-11 text Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP) Bonnie Webber editor Trevor Cohn editor Yulan He editor Yang Liu editor Association for Computational Linguistics Online conference publication hewitt-etal-2020-rnns 10.18653/v1/2020.emnlp-main.156 https://aclanthology.org/2020.emnlp-main.156/ 2020-11 1978 2010