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.ITCS.2021.44
URN: urn:nbn:de:0030-drops-135835
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Kleinberg, Robert ; Korten, Oliver ; Mitropolsky, Daniel ; Papadimitriou, Christos

Total Functions in the Polynomial Hierarchy

LIPIcs-ITCS-2021-44.pdf (0.6 MB)


We identify several genres of search problems beyond NP for which existence of solutions is guaranteed. One class that seems especially rich in such problems is PEPP (for "polynomial empty pigeonhole principle"), which includes problems related to existence theorems proved through the union bound, such as finding a bit string that is far from all codewords, finding an explicit rigid matrix, as well as a problem we call Complexity, capturing Complexity Theory’s quest. When the union bound is generous, in that solutions constitute at least a polynomial fraction of the domain, we have a family of seemingly weaker classes α-PEPP, which are inside FP^NP|poly. Higher in the hierarchy, we identify the constructive version of the Sauer-Shelah lemma and the appropriate generalization of PPP that contains it, as well as the problem of finding a king in a tournament (a vertex k such that all other vertices are defeated by k, or by somebody k defeated).

BibTeX - Entry

  author =	{Robert Kleinberg and Oliver Korten and Daniel Mitropolsky and Christos Papadimitriou},
  title =	{{Total Functions in the Polynomial Hierarchy}},
  booktitle =	{12th Innovations in Theoretical Computer Science Conference (ITCS 2021)},
  pages =	{44:1--44:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-177-1},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{185},
  editor =	{James R. Lee},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-135835},
  doi =		{10.4230/LIPIcs.ITCS.2021.44},
  annote =	{Keywords: total complexity, polynomial hierarchy, pigeonhole principle}

Keywords: total complexity, polynomial hierarchy, pigeonhole principle
Collection: 12th Innovations in Theoretical Computer Science Conference (ITCS 2021)
Issue Date: 2021
Date of publication: 04.02.2021

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