Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-17T18:13:56.943Z Has data issue: false hasContentIssue false

Countable unions of simple sets in the core model

Published online by Cambridge University Press:  12 March 2014

P. D. Welch*
Affiliation:
Department of Mathematics, University of California, Los Angeles, California 90024, E-mail: welch@math.ucla.edu

Abstract

We follow [8] in asking when a set of ordinals Xα is a countable union of sets in K, the core model. We show that, analogously to L, an X closed under the canonical Σ1 Skolem function for Kα can be so decomposed provided K is such that no ω-closed filters are put on its measure sequence, but not otherwise. This proviso holds if there is no inner model of a weak Erdős-type property.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1]Baumgartner, J., On the size of closed unbounded sets, Annals of Pure and Applied Logic, vol. 54 (1991), pp. 195227.CrossRefGoogle Scholar
[2]Devlin, K. J., Constructibility, Perspectives in Mathematical Logic, Springer-Verlag, Berlin, 1984.CrossRefGoogle Scholar
[3]Dodd, A. J., The core model, London Mathematical Society Lecture Notes Series 61, Cambridge University Press, 1982.CrossRefGoogle Scholar
[4]Donder, H.-D. and Levinski, J.-P., Some principles related to Chang's conjecture, Annals of Pure and Applied Logic, vol. 45 (1989), pp. 39101.CrossRefGoogle Scholar
[5]Feng, Q., A hierarchy of Ramsey cardinals, Annals of Pure and Applied Logic, vol. 49 (1990), pp. 257277.CrossRefGoogle Scholar
[6]Jech, T., Set theory, Academic Press, New York, 1978.Google Scholar
[7]Jensen, R. B., The core model for measures of order zero, circulated manuscript, 1989.Google Scholar
[8]Magidor, M., Representing sets of ordinals as countable unions of sets in the core model, Transactions of the American Mathematical Society, vol. 317 (1990), no. 1, pp. 91126.CrossRefGoogle Scholar
[9]Walker, D., On the transversal hypothesis and the weak Kurepa hypothesis, this Journal, vol. 53 (1988), no. 3, pp. 854877.Google Scholar