Hostname: page-component-8448b6f56d-qsmjn Total loading time: 0 Render date: 2024-04-24T22:03:31.472Z Has data issue: false hasContentIssue false

An intuitionistic version of Zermelo's proof that every choice set can be well-ordered

Published online by Cambridge University Press:  12 March 2014

J. Todd Wilson*
Affiliation:
Department of Computer Science, California State University, Fresno, Fresno, CA 93740, E-mail: twilson@csufresno.edu

Abstract

We give a proof, valid in any elementary topos, of the theorem of Zermelo that any set possessing a choice function for its set of inhabited subsets can be well-ordered. Our proof is considerably simpler than existing proofs in the literature and moreover can be seen as a direct generalization of Zermelo's own 1908 proof of his theorem.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2001

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]Aczel, P., Every choice set can be well-ordered: An elementary proof in intuitionistic set theory, Atti del Congresso Temi e prospettive della logica e della filosofia della scienze contemporanee (Cesena 7-10 gennaio, 1987), CLUEB, Bologna, 1988, pp. 1322.Google Scholar
[2]Bell, J. L., Toposes and local set theories: An introduction, Oxford Logic Guides, vol. 14, Oxford University Press, Oxford, 1988.Google Scholar
[3]Blass, A., Well-ordering and induction in intuitionistic logic and topoi, Mathematical logic and theoretical computer science (College Park, Md., 1984–1985), Dekker, New York, 1987, pp. 2948.Google Scholar
[4]Freyd, P., Choice and well-ordering, Annals of Pure and Applied Logic, vol. 35 (1987), pp. 149166.CrossRefGoogle Scholar
[5]van Heltenoort, J., From Frege to Gödel: A sourcebook in mathematical logic, 1897–1931, Harvard University Press, Cambridge, 1967.Google Scholar
[6]Smullyan, R. M. and Fitting, M., Set theory and the continuum problem, Oxford Logic Guides, vol. 34, Oxford University Press, Oxford, 1996.Google Scholar
[7]Wilson, J. T., An intuitionistic fixed-point theorem, preprint, 1999.Google Scholar
[8]Zermelo, E., Beweis, daß jede Menge wohlgeordnet werden kann, Mathematische Annalen, vol. 59 (1904), pp. 514516, English translation in [5], pp. 139–141.CrossRefGoogle Scholar
[9]Zermelo, E., Neuer Beweis für die Möglichkeit einer Wohlordnung, Mathematische Annalen, vol. 65 (1908), pp. 107128, English translation in [5], pp. 183–198.CrossRefGoogle Scholar