License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.SoCG.2016.46
URN: urn:nbn:de:0030-drops-59386
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2016/5938/
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Kawamura, Akitoshi ; Moriyama, Sonoko ; Otachi, Yota ; Pach, János

A Lower Bound on Opaque Sets

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LIPIcs-SoCG-2016-46.pdf (0.6 MB)

Abstract

It is proved that the total length of any set of countably many rectifiable curves, whose union meets all straight lines that intersect the unit square U, is at least 2.00002. This is the first improvement on the lower bound of 2 by Jones in 1964. A similar bound is proved for all convex sets U other than a triangle.

BibTeX - Entry

@InProceedings{kawamura_et_al:LIPIcs:2016:5938,
  author =	{Akitoshi Kawamura and Sonoko Moriyama and Yota Otachi and J{\'a}nos Pach},
  title =	{{A Lower Bound on Opaque Sets}},
  booktitle =	{32nd International Symposium on Computational Geometry (SoCG 2016)},
  pages =	{46:1--46:10},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-009-5},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{51},
  editor =	{S{\'a}ndor Fekete and Anna Lubiw},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2016/5938},
  URN =		{urn:nbn:de:0030-drops-59386},
  doi =		{10.4230/LIPIcs.SoCG.2016.46},
  annote =	{Keywords: barriers; Cauchy-Crofton formula; lower bound; opaque sets}
}

Keywords: barriers; Cauchy-Crofton formula; lower bound; opaque sets
Collection: 32nd International Symposium on Computational Geometry (SoCG 2016)
Issue Date: 2016
Date of publication: 10.06.2016

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