Charts, Interaction-Free Grammars, and the Compact Representation of Ambiguity
<|reference_start|>Charts, Interaction-Free Grammars, and the Compact Representation of Ambiguity: Recently researchers working in the LFG framework have proposed algorithms for taking advantage of the implicit context-free components of a unification grammar [Maxwell 96]. This paper clarifies the mathematical foundations of these techniques, provides a uniform framework in which they can be formally studied and eliminates the need for special purpose runtime data-structures recording ambiguity. The paper posits the identity: Ambiguous Feature Structures = Grammars, which states that (finitely) ambiguous representations are best seen as unification grammars of a certain type, here called ``interaction-free'' grammars, which generate in a backtrack-free way each of the feature structures subsumed by the ambiguous representation. This work extends a line of research [Billot and Lang 89, Lang 94] which stresses the connection between charts and grammars: a chart can be seen as a specialization of the reference grammar for a given input string. We show how this specialization grammar can be transformed into an interaction-free form which has the same practicality as a listing of the individual solutions, but is produced in less time and space.<|reference_end|>
@article{dymetman1997charts,,
    title={Charts, Interaction-Free Grammars, and the Compact Representation of
  Ambiguity},
    author={Marc Dymetman (Rank Xerox Research Centre, Grenoble)},
    journal={arXiv preprint arXiv:cmp-lg/9705009},
    year={1997},
    number={MLTT-029},
    archivePrefix={arXiv},
    eprint={cmp-lg/9705009},
    primaryClass={cmp-lg cs.CL}
}