Word Ordering Without Syntax
Table 3: Unlabeled attachment scores (UAS) on the PTB validation set after parsing and aligning the output. For ZGen we also include a result using the tree z∗ produced directly by the system. For Words+BNPs, internal BNP arcs are always counted as correct.
['Model', 'Words', 'Words+BNPs']
We first align the gold head to each output token. (In cases where the alignment is not one-to-one, we randomly sample among the possibilities.) The models with no knowledge of syntax are able to recover a higher proportion of gold arcs.