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Hypermachines

Published online by Cambridge University Press:  12 March 2014

Sy-David Friedman
Affiliation:
Kurt Gödel Research Center for Mathematical Logic, Währingerstraβe 25, 1090 Vienna, Austria, E-mail: sdf@logic.univie.ac.at
P. D. Welch
Affiliation:
School of Mathematics, University of Bristol, Bristol, BS8 1TW, UK, E-mail: p.welch@bristol.ac.uk

Abstract

The Infinite Time Turing Machine model [8] of Hamkins and Kidder is, in an essential sense, a “Σ2-machine” in that it uses a Σ2Liminf Rule to determine cell values at limit stages of time. We give a generalisation of these machines with an appropriate Σn rule. Such machines either halt or enter an infinite loop by stage , again generalising precisely the ITTM case.

The collection of such machines taken together computes precisely those reals of the least model of analysis.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2011

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References

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