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Bounding and nonbounding minimal pairs in the enumeration degrees

Published online by Cambridge University Press:  12 March 2014

S. Barry Cooper ,
Angsheng Li ,
Andrea Sorbi  and
Yue Yang
S. Barry Cooper
Affiliation:
Department of Pure Mathematics, School of Mathematics, University of Leeds, Leeds. LS2 9JT, UKE-mail:, [email protected]
Angsheng Li
Affiliation:
Institute of Software, Academia Sinica, Beijing, 100080., ChinaE-mail:, [email protected]
Andrea Sorbi
Affiliation:
Dipartimento Di Scienze Matematiche, Ed Informatiche “Roberto Magari”, Siena. 53100, ItalyE-mail:, [email protected]
Yue Yang
Affiliation:
Department of Mathematics, Faculty of Science, National University of Singapore, Lower Kent Ridge Road, 119260, SingaporeE-mail:, [email protected]
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Abstract

We show that every nonzero Δ20, e-degree bounds a minimal pair. On the other hand, there exist Σ20, e-degrees which bound no minimal pair.

Type
Research Article
Information
The Journal of Symbolic Logic , Volume 70 , Issue 3 , September 2005 , pp. 741 - 766
Copyright
Copyright © Association for Symbolic Logic 2005

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References

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