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On the definable ideal generated by nonbounding c.e. degrees

Published online by Cambridge University Press:  12 March 2014

Liang Yu  and
Yue Yang
Liang Yu
Affiliation:
School of Mathematics and Computing Sciences, Victoria University of Wellington, Wellington, New Zealand, E-mail: yuliang@mcs.vuw.ac.nz
Yue Yang
Affiliation:
Department of Mathematics, Faculty of Science, National University of Singapore, Lower Kent Ridge Road, Singapore 119260, Singapore, E-mail: matyangy@leonis.nus.edu.sg
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Abstract

Let [NB]1 denote the ideal generated by nonbounding c.e. degrees and NCup the ideal of noncuppable c.e. degrees. We show that both [NB]1 ∩ NCup and the ideal generated by nonbounding and noncuppable degrees are new, in the sense that they are different from M, [NB]1 and NCup—the only three known definable ideals so far.

Type
Research Article
Information
The Journal of Symbolic Logic , Volume 70 , Issue 1 , March 2005 , pp. 252 - 270
Copyright
Copyright © Association for Symbolic Logic 2005

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References

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