Abstract
We prove that no subclass of the \(\Sigma^0_2\) enumeration degrees containing the nonzero 3-c.e. enumeration degrees can be cupped to 0 e ′ by a single incomplete \(\Sigma^0_2\) enumeration degree.
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Soskova, M.I. (2008). Cupping Classes of \(\Sigma^0_2\) Enumeration Degrees. In: Beckmann, A., Dimitracopoulos, C., Löwe, B. (eds) Logic and Theory of Algorithms. CiE 2008. Lecture Notes in Computer Science, vol 5028. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-69407-6_59
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DOI: https://doi.org/10.1007/978-3-540-69407-6_59
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