Minimal pairs in initial segments of the recursively enumerable degrees (Q1366939)

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scientific article; zbMATH DE number 1062355
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Minimal pairs in initial segments of the recursively enumerable degrees
scientific article; zbMATH DE number 1062355

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    Minimal pairs in initial segments of the recursively enumerable degrees (English)
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    8 November 1999
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    Two degrees \textbf{a} and \textbf{b} form a minimal pair if \({\mathbf a}\cap {\mathbf b}= \mathbf{0}\). The degrees \textbf{a} and \textbf{b} are called halfs of the pair. The authors study the problem of describing the computably enumerable (c.e.) degrees forming a half of a minimal pair and show that in every lower cone bounded by a non-zero c.e. degree there is a degree which is not a half of a minimal pair (in the cone). This result is related to a result of the reviewer, who proved that there is a cone bounded by a c.e. degree in which every degree is a half of a minimal pair in a wider class of \(\omega\)-c.e. degrees.
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    recursively enumerable degrees
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    computably enumerable degrees
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    initial segments
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    half of a minimal pair
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