Alternation bounds for tree automata

We consider alternation depth bounds for tree automata, that is, we limit the number of alternations of existential and universal computation steps. We show that a constant bound guarantees that the forest recognized is regular, whereas already a logarithmic bound enables the automata to recognize a...

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Bibliographic Details
Main Author: Salomaa Kai
Format: Article
Published: 1992
Series:Acta cybernetica 10 No. 3
Kulcsszavak:Számítástechnika, Kibernetika, Automaták
Subjects:
Online Access:http://acta.bibl.u-szeged.hu/12505
Description
Summary:We consider alternation depth bounds for tree automata, that is, we limit the number of alternations of existential and universal computation steps. We show that a constant bound guarantees that the forest recognized is regular, whereas already a logarithmic bound enables the automata to recognize a strictly larger class of forests. As a corollary we obtain results on other types of alternation bounds for tree automata. We consider also commutation properties of independent computation steps of an alternating tree automaton.
Physical Description:173-197
ISSN:0324-721X