,
Michał Skrzypczak
Creative Commons Attribution 4.0 International license
We study guidable parity automata over infinite trees introduced by Colcombet and Löding, which form an expressively complete subclass of all non-deterministic tree automata. We show that, for any non-deterministic automaton, an equivalent guidable automaton with the smallest possible index can be effectively found. Moreover, if an input automaton is of a special kind, i.e. it is deterministic or game automaton then a guidable automaton with an optimal index can be deterministic (respectively game) automaton as well. Recall that the problem whether an equivalent non-deterministic automaton with the smallest possible index can be effectively found is open, and a positive answer is known only in the case when an input automaton is a deterministic, or more generally, a game automaton.
@InProceedings{niwinski_et_al:LIPIcs.MFCS.2021.81,
author = {Niwi\'{n}ski, Damian and Skrzypczak, Micha{\l}},
title = {{On Guidable Index of Tree Automata}},
booktitle = {46th International Symposium on Mathematical Foundations of Computer Science (MFCS 2021)},
pages = {81:1--81:14},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-201-3},
ISSN = {1868-8969},
year = {2021},
volume = {202},
editor = {Bonchi, Filippo and Puglisi, Simon J.},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2021.81},
URN = {urn:nbn:de:0030-drops-145214},
doi = {10.4230/LIPIcs.MFCS.2021.81},
annote = {Keywords: guidable automata, index problem, \omega-regular games}
}