An omega-power of a context-free language which is Borel above Delta^0_omega

Jacques Duparc; Olivier Finkel

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arXiv · 0801.1783

An omega-power of a context-free language which is Borel above Delta^0_omega

Jacques Duparc·Olivier Finkel

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Abstract

We use erasers-like basic operations on words to construct a set that is both Borel and above Delta^0_omega, built as a set V^ωwhere V is a language of finite words accepted by a pushdown automaton. In particular, this gives a first example of an omega-power of a context free language which is a Borel set of infinite rank.

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BibTeX RIS

Jacques Duparc, Olivier Finkel. 2008-01-11. An omega-power of a context-free language which is Borel above Delta^0_omega. https://arxiv.org/abs/0801.1783

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