@inproceedings{f8bdc3b36ebb4c50a30ac652bedd4362,
title = "The non-associativity of polarized tree-based grammars",
abstract = "Polarities are used to sanction grammar fragment combination in high level tree-based formalisms such as eXtenssible MetaGrammar (XMG) and polarized unification grammars (PUG). We show that attaching polarities to tree nodes renders the combination operation non-associative, and in practice leads to overgeneration. We first provide some examples of non-associative combination operators in existing polarity-based formalisms. We then prove that there is no other nontrivial polarity system for which grammar combination is associative. This property of polarities casts doubt on the usability of polarity-based grammars for grammar engineering.",
author = "Yael Cohen-Sygal and Shuly Wintner",
year = "2007",
doi = "10.1007/978-3-540-70939-8_19",
language = "English",
isbn = "354070938X",
series = "Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)",
publisher = "Springer Verlag",
pages = "208--217",
booktitle = "Computational Linguistics and Intelligent Text Processing - 8th International Conference, CICLing 2007, Proceedings",
address = "Germany",
note = "8th Annual Conference on Intelligent Text Processing and Computational Linguistics, CICLing 2007 ; Conference date: 18-02-2007 Through 24-02-2007",
}