Considering an undirected graph G = (V, E) as the syntactic parsing tree for sentence W , and E are sets of nodes and edges, respectively.
with this additional gating mechanism, the final syntactic GCN computation is formulated as As stacking k layers of GCNs can model information in k hops, and sometimes the length of shortcut path between two triggers is less than k, to avoid information over-propagating, we adapt highway units (Srivastava et al., 2015), which allow unimpeded information flowing across stacking GCN layers.