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Minimal degrees which are $\Sigma_{2}^{0}$ but not $\Delta_{2}^{0}$


Author: Richard A. Shore
Journal: Proc. Amer. Math. Soc. 132 (2004), 563-565
MSC (2000): Primary 03D28
DOI: https://doi.org/10.1090/S0002-9939-03-07080-1
Published electronically: June 17, 2003
MathSciNet review: 2022382
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Abstract: We give a short proof of the existence of minimal Turing degrees which are $\Sigma_{2}^{0}$ but not $\Delta_{2}^{0}$.


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Additional Information

Richard A. Shore
Affiliation: Department of Mathematics, Cornell University, Ithaca, New York 14853
Email: shore@math.cornell.edu

DOI: https://doi.org/10.1090/S0002-9939-03-07080-1
Keywords: Minimal degree, recursively enumerable in $0'$
Received by editor(s): August 19, 2002
Received by editor(s) in revised form: October 8, 2002
Published electronically: June 17, 2003
Additional Notes: This research was partially supported by NSF Grant DMS-0100035
Communicated by: Carl G. Jockusch, Jr.
Article copyright: © Copyright 2003 American Mathematical Society

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