Borel ranks and Wadge degrees of context free ω-languages
نویسنده
چکیده
We determine completely the Borel hierarchy of the class of context free ω-languages, showing that, for each recursive non null ordinal α, there exist some Σα-complete and some Π 0 α-complete ω-languages accepted by Büchi 1-counter automata.
منابع مشابه
Borel Ranks and Wadge Degrees of Context Free omega-Languages
We show that the Borel hierarchy of the class of context free ω-languages, or even of the class of ω-languages accepted by Büchi 1-counter automata, is the same as the Borel hierarchy of the class of ω-languages accepted by Turing machines with a Büchi acceptance condition. In particular, for each recursive non null ordinal α, there exist some Σ α -complete and some Π α -complete ω-languages ac...
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We show that the Borel hierarchy of the class of context free ω-languages, or even of the class of ω-languages accepted by Büchi 1-counter automata, is the same as the Borel hierarchy of the class of ω-languages accepted by Turing machines with a Büchi acceptance condition. In particular, for each recursive non null ordinal α, there exist some Σ α -complete and some Π α -complete ω-languages ac...
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We prove that ω-languages of (non-deterministic) Petri nets and ω-languages of (non-deterministic) Turing machines have the same topological complexity: the Borel and Wadge hierarchies of the class of ω-languages of (non-deterministic) Petri nets are equal to the Borel and Wadge hierarchies of the class of ω-languages of (non-deterministic) Turing machines which also form the class of effective...
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We survey recent results on the topological complexity of context-free ω-languages which form the second level of the Chomsky hierarchy of languages of infinite words. In particular, we consider the Borel hierarchy and the Wadge hierarchy of non-deterministic or deterministic context-free ω-languages. We study also decision problems, the links with the notions of ambiguity and of degrees of amb...
متن کاملJ an 2 00 8 On the length of the Wadge hierarchy of ω - context free languages ∗
We prove in this paper that the length of the Wadge hierarchy of ω-context free languages is greater than the Cantor ordinal εω, which is the ω th fixed point of the ordinal exponentiation of base ω. We show also that there exist some Σ0ω-complete ω-context free languages, improving previous results on ω-context free languages and the Borel hierarchy.
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تاریخ انتشار 2005