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Change syntax rules to facilitate semantics?

zaterdag 31 maart 2012 22:38

It may be useful to change the way phrase structure rules are built when dealing with semantics analysis and production.

The sentence

Lord Byron was influenced by the author of Paradise Lost

is usually parsed like this:

(thanks to phpSyntaxTree for the image)

But when analyzing the semantics of the sentence, it is somewhat awkward.

predicate: influenced
first argument: the author of Paradise Lost
second argument: Lord Byron

(It is a passive sentence, subject and object are reversed.) The related semantic parts are distributed over the sentence.

When generating the sentence from the semantic specification, this becomes even more complicated.

Things can be made easier by just changing the phrase structure rules:

This may make Chomsky frown, but it works perfectly well for both parsing and generating. The predicate and its two arguments can be rewritten using the same rule. In passive sentences, the word "by" is not just another preposition, it is a structural part of the passivization of the sentence. All passive sentences (that name the agent of the action) have it.

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