Viable Dependency Parsing as Sequence Labeling
Table 4: Comparison on UD-CoNLL18 test sets.
['[BOLD] Treebank', 'PoS type', '[BOLD] PC2,800  [BOLD] (sent/s)', '[BOLD] PC2,800  [BOLD] UAS', '[BOLD] PC2,800  [BOLD] LAS', '[BOLD] KG (transition-based)  [BOLD] (sent/s)', '[BOLD] KG (transition-based)  [BOLD] UAS', '[BOLD] KG (transition-based)  [BOLD] LAS']
We believe that the variations between languages in terms of LAS difference with respect to BIST can be largely due to differences in the accuracy and granularity of predicted PoS tags, since our chosen encoding relies on them to encode arcs. The bracketing-based encoding, which does not use PoS tags, may be more robust to this. On the other hand, finding the optimal granularity of PoS tags for the PoS-based encoding can be an interesting avenue for future work.