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Link grammars resemble dependency grammars and categorial grammars. There are also many significant differences. Some light is shed on the relationship in section 6.

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The proof of the context-freeness of link grammars is not included in this paper, but appears in our technical report [14]. Note that context-free systems can differ in many ways, including the ease with which the same grammar can be expressed, the efficiency with which the same grammar can be parsed, and the usefulness of the output of the parser for further processing.

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The directory is /usr/sleator/public on the host spade.cs.cmu.edu (128.2.209.226). Our technical reports [11][14] are also available there.

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Although they do appear in our technical report [14].

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There are other variants of categorial grammars which are mildly context-sensitive[9]. Of course the construction presented here does not work for those languages.

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Personal communication.