... have tried a rule-based approach to this problem. Instead it appears that there is an understandable predisposition against rule-based approaches, given the fact that data-driven, especially ... In addition, if a node has a particular grammatical function (such as subject) or semantic role (such as location), it has a function tag indicating that role; empty categories may also have ... In addition to bracketing the input string, a fully adequate syntactic analyzer should also locate empty categories in the parse tree, identify their antecedents, if any, and assign them appropriate...