An effective characterization of the alternation hierarchy in two-variable logic

@InProceedings{krebs_et_al:LIPIcs.FSTTCS.2012.86,
  author =	{Krebs, Andreas and Straubing, Howard},
  title =	{{An effective characterization of the alternation hierarchy in two-variable logic}},
  booktitle =	{IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2012)},
  pages =	{86--98},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-47-7},
  ISSN =	{1868-8969},
  year =	{2012},
  volume =	{18},
  editor =	{D'Souza, Deepak and Radhakrishnan, Jaikumar and Telikepalli, Kavitha},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2012.86},
  URN =		{urn:nbn:de:0030-drops-38501},
  doi =		{10.4230/LIPIcs.FSTTCS.2012.86},
  annote =	{Keywords: FO\underline2, Quantifier Alternation, J, Pseudovarities, Identities}
}