TY - GEN
T1 - Degrees of ambiguity for parity tree automata
AU - Rabinovich, Alexander
AU - Tiferet, Doron
N1 - Publisher Copyright:
© Alexander Rabinovich and Doron Tiferet.
PY - 2021/1
Y1 - 2021/1
N2 - 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.
AB - 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.
KW - Automata on infinite trees
KW - Degree of ambiguity
KW - Omega word automata
KW - Parity automata
UR - http://www.scopus.com/inward/record.url?scp=85100891096&partnerID=8YFLogxK
U2 - 10.4230/LIPIcs.CSL.2021.36
DO - 10.4230/LIPIcs.CSL.2021.36
M3 - ???researchoutput.researchoutputtypes.contributiontobookanthology.conference???
AN - SCOPUS:85100891096
T3 - Leibniz International Proceedings in Informatics, LIPIcs
BT - 29th EACSL Annual Conference on Computer Science Logic, CSL 2021
A2 - Baier, Christel
A2 - Goubault-Larrecq, Jean
PB - Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
T2 - 29th EACSL Annual Conference on Computer Science Logic, CSL 2021
Y2 - 25 January 2021 through 28 January 2021
ER -