@InProceedings{erickson_et_al:LIPIcs.SoCG.2019.34,
  author =	{Erickson, Jeff and Wang, Yipu},
  title =	{{Topologically Trivial Closed Walks in Directed Surface Graphs}},
  booktitle =	{35th International Symposium on Computational Geometry (SoCG 2019)},
  pages =	{34:1--34:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-104-7},
  ISSN =	{1868-8969},
  year =	{2019},
  volume =	{129},
  editor =	{Barequet, Gill and Wang, Yusu},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2019.34},
  URN =		{urn:nbn:de:0030-drops-104383},
  doi =		{10.4230/LIPIcs.SoCG.2019.34},
  annote =	{Keywords: computational topology, surface-embedded graphs, homotopy, homology, strong connectivity, hyperbolic geometry, medial axes, context-free grammars}
}