@InProceedings{arnold_et_al:LIPIcs.STACS.2012.396,
  author =	{Arnold, Andr\'{e} and Michalewski, Henryk and Niwinski, Damian},
  title =	{{On the separation question for tree languages}},
  booktitle =	{29th International Symposium on Theoretical Aspects of Computer Science (STACS 2012)},
  pages =	{396--407},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-35-4},
  ISSN =	{1868-8969},
  year =	{2012},
  volume =	{14},
  editor =	{D\"{u}rr, Christoph and Wilke, Thomas},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2012.396},
  URN =		{urn:nbn:de:0030-drops-34156},
  doi =		{10.4230/LIPIcs.STACS.2012.396},
  annote =	{Keywords: Alternating automata on infinite trees, Index hierarchy, Separation property}
}