Degrees of ambiguity for parity tree automata

Alexander Rabinovich, Doron Tiferet

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

An automaton is unambiguous if for every input it has at most one accepting computation. An automaton is finitely (respectively, countably) ambiguous if for every input it has at most finitely (respectively, countably) many accepting computations. An automaton is boundedly ambiguous if there is k ∈ N, such that for every input it has at most k accepting computations. We consider Parity Tree Automata (PTA) and prove that the problem whether a PTA is not unambiguous (respectively, is not boundedly ambiguous, not finitely ambiguous) is co-NP complete, and the problem whether a PTA is not countably ambiguous is co-NP hard.

Original languageEnglish
Title of host publication29th EACSL Annual Conference on Computer Science Logic, CSL 2021
EditorsChristel Baier, Jean Goubault-Larrecq
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959771757
DOIs
StatePublished - Jan 2021
Event29th EACSL Annual Conference on Computer Science Logic, CSL 2021 - Virtual, Ljubljana, Slovenia
Duration: 25 Jan 202128 Jan 2021

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
Volume183
ISSN (Print)1868-8969

Conference

Conference29th EACSL Annual Conference on Computer Science Logic, CSL 2021
Country/TerritorySlovenia
CityVirtual, Ljubljana
Period25/01/2128/01/21

Keywords

  • Automata on infinite trees
  • Degree of ambiguity
  • Omega word automata
  • Parity automata

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