We have not mentioned the effect of our unary merging (Section 3), but the result indicates it has almost the same effect as the previously proposed padding method (Zhu et al., Shift-  We divide baseline state-of-the-art systems into three categories: shift-reduce systems (Sagae and Lavie, 2005;Sagae and Lavie, 2006;Zhu et al., 2013), other chart-based systems (Petrov and Klein, 2007;Socher et al., 2013), and the systems with external semi supervised features or reranking (Charniak and Johnson, 2005;McClosky et al., 2006;Zhu et al., 2013).
all systems are trained with the structured perceptron.