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η-representation of sets and degrees

Published online by Cambridge University Press:  12 March 2014

Kenneth Harris*
Affiliation:
Department of Computer Science, University of Chicago1100 E. 5TH Street, Chicago, IL 60637, USA, E-mail: kaharris@cs.uchicago.edu

Abstract

We show that a set has an η-representation in a linear order if and only if it is the range of a 0′-computable limitwise monotonic function. We also construct a Δ3 Turing degree for which no set in that degree has a strong η-representation, answering a question posed by Downey.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2008

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References

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