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HC of an admissible set1

Published online by Cambridge University Press:  12 March 2014

Sy D. Friedman*
Affiliation:
University of Chicago, Chicago, IL 60637

Abstract

If A is an admissible set, let HC(A) = {xxA and x is hereditarily countable in A}. Then HC(A) is admissible. Corollaries are drawn characterizing the “real parts” of admissible sets and the analytical consequences of admissible set theory.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1979

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Footnotes

1

The research for this paper was supported by NSF Grant = MCS 76-07033. This paper accompanies a talk delivered by the author at the December, 1977 meeting of the Association for Symbolic Logic, Washington, D. C. The author wishes to thank the referee for his pointed and valuable suggestions.

References

REFERENCES

[1]Barwise, J., Admissible sets and structures, Omega Series, Springer-Verlag, Berlin and New York, 1975.CrossRefGoogle Scholar
[2]Barwise, J., and Fisher, E., The Shoenfield absoluteness lemma, Israel Journal of Mathematics, vol. 8 (1970), pp. 329339.CrossRefGoogle Scholar
[3]Friedman, H., Bar-induction and Π11-CA, this Journal, vol. 34 (1969), pp. 353362.Google Scholar
[4]Howard, W. A., Functional interpretation of bar induction by bar recursion, Compositio Mathematics, vol. 20(1968), pp. 107124.Google Scholar
[5]Howard, W. A., and Kreisel, G., Transfinite induction and bar induction of types zero and one, this Journal, vol. 31 (1966), pp. 325358.Google Scholar
[6]Lévy, A., Definability in axiomatic set theory. II, Mathematical logic and the foundations of set theory (Bar-Hillel, , Editor), North-Holland, Amsterdam, 1970.Google Scholar
[7]Platek, R., Foundations of recursion theory, Ph.D. Thesis, University of Stanford, 1965.Google Scholar
[8]Sacks, G., The 1-section of a type n object, Generalized recursion theory (Fenstad, and Hinman, , Editors), North-Holland, Amsterdam, 1974.Google Scholar
[9]Sacks, G., Countable admissible ordinals and hyperdegrees, Advances in Mathematics, vol. 20 (1976), pp. 213262.CrossRefGoogle Scholar
[10]Steel, J., Subsystems of analysis and the axiom of determinacy, Ph.D. Thesis University of California, Berkeley, 1977.Google Scholar