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BUG: a Directed Bottom Up Generator

In this section I will introduce BUG, a directed bottom up generator, and I will discuss some of its properties. The task for the generator can be seen as follows. The generator will receive a feature structure Top as its input. Part of this feature structure is the semantic structure S_Top. For a given grammar, the generator derives all strings W for which the condition <6> holds (for a formal definition of this concept within LFG cf. Wedekind 1988).

As will become clear in the following paragraphs, a few conditions on grammars apply for BUG to work properly. For each grammar rule there is one daughter that is the semantic head (specified as such by the rule writer). For the moment I will assume that if the semantics of the mother node is instantiated then the semantics of the semantic head is instantiated too. I will define the notion 'semantic head' more precisely in section 2.3. First I will introduce the basic structure of BUG.

Gertjan van Noord
Fri Nov 25 13:48:52 MET 1994