@article{Arnold2014,
    Abstract = {We show that the separation property fails for the classes $\Sigma$nof the Rabin-Mostowski index hierarchy of alternating automata on infinite trees. This extends our previous result (obtained with Szczepan Hummel) on the failure of the separation property for the class $\Sigma$2 (i.e., for co-B{\"u}chi sets). The non-separation result is also adapted to the analogous classes induced by weak alternating automata.},
    Author = {Arnold, Andr{\'e} and Michalewski, Henryk and Niwi{\'{n}}ski, Damian},
    ISSN = {1433-0490},
    Journal = {Theory of Computing Systems},
    Month = {Nov},
    Number = {4},
    Pages = {833--855},
    Title = {On the Separation Question for Tree Languages},
    URL = {https://doi.org/10.1007/s00224-013-9461-4},
    Volume = {55},
    Year = {2014},
    bdsk-url-1 = {https://doi.org/10.1007/s00224-013-9461-4},
    date-added = {2020-01-08 17:51:57 +0100},
    date-modified = {2020-01-08 17:51:57 +0100},
    day = {01},
    file-2 = {On the separation question for tree languages - Arnold2014\_Article\_OnTheSeparationQuestionForTree - a - v.pdf},
    doi = {10.1007/s00224-013-9461-4}
}

@article{Arnold2014, Abstract = {We show that the separation property fails for the classes $\Sigma$nof the Rabin-Mostowski index hierarchy of alternating automata on infinite trees. This extends our previous result (obtained with Szczepan Hummel) on the failure of the separation property for the class $\Sigma$2 (i.e., for co-B{\"u}chi sets). The non-separation result is also adapted to the analogous classes induced by weak alternating automata.}, Author = {Arnold, Andr{\'e} and Michalewski, Henryk and Niwi{\'{n}}ski, Damian}, ISSN = {1433-0490}, Journal = {Theory of Computing Systems}, Month = {Nov}, Number = {4}, Pages = {833--855}, Title = {On the Separation Question for Tree Languages}, URL = {https://doi.org/10.1007/s00224-013-9461-4}, Volume = {55}, Year = {2014}, bdsk-url-1 = {https://doi.org/10.1007/s00224-013-9461-4}, date-added = {2020-01-08 17:51:57 +0100}, date-modified = {2020-01-08 17:51:57 +0100}, day = {01}, file-2 = {On the separation question for tree languages - Arnold2014_Article_OnTheSeparationQuestionForTree - a - v.pdf}, doi = {10.1007/s00224-013-9461-4} }