Tree-walking automata do not recognize all regular languages
Tree-walking automata do not recognize all regular languages
复制标题
树行走自动机无法识别所有常规语言
DOI:
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发表时间:
2005
期刊:
影响因子:
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通讯作者:
Thomas Colcombet
中科院分区:
文献类型:
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作者:
Mikolaj Bojanczyk;Thomas Colcombet
Tree-walking automata are a natural sequential model for recognizing tree languages. Every tree language recognized by a tree-walking automaton is regular. In this paper, we present a tree language which is regular but not recognized by any (nondeterministic) tree-walking automaton. This settles a conjecture of Engelfriet, Hoogeboom and Van Best. Moreover, the separating tree language is definable already in first-order logic over a signature containing the left-son, right-son and ancestor relations.