Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-11T08:26:12.890Z Has data issue: false hasContentIssue false

Elementary axioms for canonical points of toposes

Published online by Cambridge University Press:  12 March 2014

Colin McLarty*
Affiliation:
Department of Mathematics, Cleveland State University, Cleveland, Ohio 44115

Extract

Two elementary extensions of the topos axioms are given, each implying the topos has a local geometric morphism to a category of sets. The stronger one realizes sets as precisely the decidables of the topos, so there is a simple internal description of the range of validity of the law of excluded middle in the topos. It also has a natural geometric meaning. Models of the extensions in Grothendieck toposes are described.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1987

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] Barr, M. and Wells, C., Toposes, triples, and theories, Springer-Verlag, New York, 1985.CrossRefGoogle Scholar
[2] Dubuc, E. J. and Penon, J., Objets compacts dans les topos, Journal of the Australian Mathematical Society Series A (to appear).Google Scholar
[3] Lawvere, W. F., Elementary theory of the category of sets, mimeographed, University of Chicago, Chicago, Illinois, 1963.Google Scholar
[4] Moerdijk, I. and Reyes, G., Smooth spaces versus continuous spaces in models for synthetic differential geometry, Journal of Pure and Applied Algebra, vol. 32 (1984), pp. 143176.CrossRefGoogle Scholar
[5] Tierney, M., Sheaf theory and the continuum hypothesis, Toposes, algebraic geometry, and logic (Bucur, I. et al., editors), Lecture Notes in Mathematics, vol. 274, Springer-Verlag, New York, 1972, pp. 1342.CrossRefGoogle Scholar