Tree generation

To generate elementary trees, we begin with a canonical subcategorization frame. The system will first generate related subcategorization frames by applying LRRs, then select subcategorization blocks corresponding to the information in the subcategorization frames, next the combinations of these blocks are further combined with the blocks corresponding to various transformations, finally, a set of trees are generated from those combined blocks, and they are the tree family for this subcategorization frame. Figure shows some of the trees produced in this way. For instance, the last tree is obtained by incorporating information from the ditransitive verb subcategorization frame, applying the dative-shift and passive LRRs, and then combining them with the wh-non-subject extraction block. Besides, in our system the hierarchy for subcategorization frames is implicit as shown in Figure .

  

Figure: Partial inheritance lattice in English

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