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The distribution of properly Σ20 e-degrees

Published online by Cambridge University Press:  12 March 2014

Stanislaw Bereznyuk
Affiliation:
Institute of Mathematics, Novosibirsk State University, Novosibirsk, Russia, E-mail: [email protected]
Richard Coles
Affiliation:
Mathematics Department, Victoria University of Wellington, Wellington, New Zealand, E-mail: [email protected] Department of Computer Science, University of Auckland, Auckland, New Zealand, E-mail: [email protected]
Andrea Sorbi
Affiliation:
Department of Mathematics, University of Siena, Siena, Italy, E-mail: [email protected]

Abstract

We show that for every enumeration degree a < 0e there exists an e-degree c such that ac < 0e, and all degrees b, with cb < 0e, are properly Σ20.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2000

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References

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