Journal of Logic and Computation Advance Access originally published online on August 5, 2008
Journal of Logic and Computation 2009 19(1):145-150; doi:10.1093/logcom/exn031
This article appears in the following Journal of Logic and Computation issue: Special Issue: Logic and Computation in the Real World: CiE 2007 [View the issue table of contents]
Original Articles |
The Settling Time Reducibility Ordering and 
Sets
Department of Pure Mathematics, University of Waterloo, Waterloo, ON, Canada N2L 3G1
E-mail: csima{at}math.uwaterloo.ca
The settling time reducibility ordering gives an ordering on computably enumerable sets based on their enumerations. The <st ordering is in fact an ordering on c.e. sets, since it is independent of the particular enumeration chosen. In this article, we show that it is not possible to extend this ordering in an approximation-independent way to 
sets in general, or even to n-c.e. sets for any fixed n
3.
Keywords: Computability theory; 
sets; computable approximations
References
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- Soare RI. Computability theory and differential geometry, Bulletin of Symbolic Logic (2004) 10:457–486.[CrossRef][Web of Science]
- Soare RI. Computability Theory and Applications. (in preparation).
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