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.MFCS.2016.10
URN: urn:nbn:de:0030-drops-64268
URL: http://dagstuhl.sunsite.rwth-aachen.de/volltexte/2016/6426/
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Kallampally, Vivek Anand T ; Tewari, Raghunath

Trading Determinism for Time in Space Bounded Computations

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Abstract

Savitch showed in 1970 that nondeterministic logspace (NL) is contained in deterministic O(log^2(n)) space but his algorithm requires quasipolynomial time. The question whether we can have a deterministic algorithm for every problem in NL that requires polylogarithmic space and simultaneously runs in polynomial time was left open.

In this paper we give a partial solution to this problem and show that for every language in NL there exists an unambiguous nondeterministic algorithm that requires O(log^2(n)) space and simultaneously runs in polynomial time.

BibTeX - Entry

@InProceedings{kallampally_et_al:LIPIcs:2016:6426,
  author =	{Vivek Anand T Kallampally and Raghunath Tewari},
  title =	{{Trading Determinism for Time in Space Bounded Computations}},
  booktitle =	{41st International Symposium on Mathematical Foundations of Computer Science (MFCS 2016)},
  pages =	{10:1--10:13},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-016-3},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{58},
  editor =	{Piotr Faliszewski and Anca Muscholl and Rolf Niedermeier},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{http://drops.dagstuhl.de/opus/volltexte/2016/6426},
  URN =		{urn:nbn:de:0030-drops-64268},
  doi =		{10.4230/LIPIcs.MFCS.2016.10},
  annote =	{Keywords: space complexity, unambiguous computations, Savitch's Theorem}
}

Keywords: space complexity, unambiguous computations, Savitch's Theorem
Collection: 41st International Symposium on Mathematical Foundations of Computer Science (MFCS 2016)
Issue Date: 2016
Date of publication: 19.08.2016


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