For reranking, the features of Collins and Koo (2005) were extended in the following way: Since the German treebank used for our experiments includes grammatical function information on almost all levels in the tree, all feature types were also included with grammatical functions attached: All nodes except the root node of the subtree in question were annotated with their grammatical information.
for the noun phrase (NX) rule with grandparent prepositional phrase (PX) PX GP NX → ART ADJX NN, we add an additional rule PX GP NX-HD → ART ADJX NN-HD.