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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

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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