@article{10.1145/321312.321318,
    Abstract = {Four principal results about ambiguity in languages (i.e., context free languages) are proved. It is first shown that the problem of determining whether an arbitrary language is inherently ambiguous is recursively unsolvable. Then a decision procedure is presented for determining whether an arbitrary bounded grammar is ambiguous. Next, a necessary and sufficient algebraic condition is given for a bounded language to be inherently ambiguous. Finally, it is shown that no language contained in w1*w2*, each w1 a word, is inherently ambiguous.},
    Address = {New York, NY, USA},
    Author = {Ginsburg, Seymour and Ullian, Joseph},
    ISSN = {0004-5411},
    Journal = {J. ACM},
    Month = {January},
    Number = {1},
    Pages = {62---89},
    Publisher = {Association for Computing Machinery},
    Title = {Ambiguity in Context Free Languages},
    URL = {https://doi.org/10.1145/321312.321318},
    Volume = {13},
    Year = {1966},
    bdsk-url-1 = {https://doi.org/10.1145/321312.321318},
    date-added = {2021-03-25 15:19:26 +0100},
    date-modified = {2021-03-25 15:19:33 +0100},
    issue_date = {Jan. 1966},
    numpages = {28},
    doi = {10.1145/321312.321318}
}

@article{10.1145/321312.321318, Abstract = {Four principal results about ambiguity in languages (i.e., context free languages) are proved. It is first shown that the problem of determining whether an arbitrary language is inherently ambiguous is recursively unsolvable. Then a decision procedure is presented for determining whether an arbitrary bounded grammar is ambiguous. Next, a necessary and sufficient algebraic condition is given for a bounded language to be inherently ambiguous. Finally, it is shown that no language contained in w1w2, each w1 a word, is inherently ambiguous.}, Address = {New York, NY, USA}, Author = {Ginsburg, Seymour and Ullian, Joseph}, ISSN = {0004-5411}, Journal = {J. ACM}, Month = {January}, Number = {1}, Pages = {62---89}, Publisher = {Association for Computing Machinery}, Title = {Ambiguity in Context Free Languages}, URL = {https://doi.org/10.1145/321312.321318}, Volume = {13}, Year = {1966}, bdsk-url-1 = {https://doi.org/10.1145/321312.321318}, date-added = {2021-03-25 15:19:26 +0100}, date-modified = {2021-03-25 15:19:33 +0100}, issue_date = {Jan. 1966}, numpages = {28}, doi = {10.1145/321312.321318} }