@InProceedings{blum_et_al:LIPIcs.ESA.2020.20,
  author =	{Blum, Johannes and Storandt, Sabine},
  title =	{{Lower Bounds and Approximation Algorithms for Search Space Sizes in Contraction Hierarchies}},
  booktitle =	{28th Annual European Symposium on Algorithms (ESA 2020)},
  pages =	{20:1--20:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-162-7},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{173},
  editor =	{Grandoni, Fabrizio and Herman, Grzegorz and Sanders, Peter},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2020.20},
  URN =		{urn:nbn:de:0030-drops-128861},
  doi =		{10.4230/LIPIcs.ESA.2020.20},
  annote =	{Keywords: contraction hierarchies, search space size, balanced separator, tree decomposition}
}