An Overview of Head driven Bottom-up Generation

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An Overview of Head driven Bottom-up Generation

Gertjan van Noord
Trans 10 Utrecht


In this paper I will discuss the properties of a tactical generation approach that has become popular recently: head-driven bottom-up generation.

It is assumed that bidirectional grammars written in some unification- or logic-based formalism define relations between strings and some representation, usually called logical form. The task for a generator is to generate for a given logical form the strings that are related to this logical form by the grammar.

In the paper it will be shown that the `early' approaches to this conceivement of the generation problem such as [21], [31] and [7] are not entirely satisfactory for general purposes. Furthermore I will define a simple bottom-up generator, called BUG1 for reference, as prototypical for the head-driven bottom-up approach as defended by for example [24][23][5][30]. I will argue that head-driven bottom-up generation is to be preferred because the order of processing is directed by the input logical form and the information available in lexical entries; moreover the algorithm puts fewer restrictions on grammars than some other generators.

Gertjan van Noord
Fri Nov 25 13:07:08 MET 1994