Otherwise, it would entail that there is a tree reachable from C but unreachable from t(C), for any t. Therefore, we reformulate equation 1: (3) In the transition system, the grammar is left implicit: any reduction is allowed (even if the corresponding grammar rule has never been seen in the training corpus).
due to the introduction of temporary symbols during binarization, there are constraints to ensure that any derivation corresponds to a well-formed unbinarized tree.