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On Σ1-Structural Differences Among Finite Levels of the Ershov Hierarchy

Published online by Cambridge University Press:  12 March 2014

Yue Yang  and
Liang Yu
Yue Yang
Affiliation:
Department of Mathematics Faculty of Science, National University of Singapore, 2 Science Drive 2, Singapore 117543. Singapore, E-mail: matyangy@nus.edu.sg
Liang Yu
Affiliation:
Institute of Mathematical Sciences, Nanjing University, Nanjing, Jiangsu Province, 210093, China, E-mail: yuliang.nju@gmail.com
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Abstract

We show that the structure of recursively enumerable degrees is not a Σ1-elementary substructure of , where (n > 1) is the structure of n-r.e. degrees in the Ershov hierarchy.

Type
Research Article
Information
The Journal of Symbolic Logic , Volume 71 , Issue 4 , December 2006 , pp. 1223 - 1236
Copyright
Copyright © Association for Symbolic Logic 2006

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References

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