Recently, transition-based top-down parsing with Pointer Networks (Vinyals et al., 2015) has attained state-of-the-art results in both dependency and discourse parsing tasks with the same computational efficiency (Ma et al., 2018;Lin et al., 2019); thanks to the encoder-decoder architecture that makes it possible to capture information from the whole text and the previously derived subtrees, while limiting the number of parsing steps to linear.
the decoder of these parsers has a sequential structure, which may not yield the most appropriate inductive bias for deriving a hierarchical structure.