... general, a particular semantic interpretation of a sentence can be characterized by a set of lexical categories (or parts of speech), a syntactic struc- ture, and the semantic annotations associated ... an example of AST. The annotated version of a node A is denoted as A = A [fa] in the figure, where fA is the feature structure associated with node A. Because an AST preserves both syntactic ... sense of head and head feature.) An annotated node can thus be approximated as A ,~ A( fl,f2, ,fN), where fj = HeadFeature X~7~,~) is the (primary) head feature of its j-th head (i.e.,...