Hostname: page-component-586b7cd67f-tf8b9 Total loading time: 0 Render date: 2024-11-26T11:24:16.429Z Has data issue: false hasContentIssue false

A topos with no geometric morphism to any Boolean one

Published online by Cambridge University Press:  24 October 2008

Robert Paré
Affiliation:
Dalhousie University, Halifax, N.S., Canada

Extract

In [1], Julian Cole asked whether every topos is definable over a Boolean one. Peter Johnstone partially answered this in [2] (corollary 3·7) by giving an example of a topos admitting no bounded morphism to any Boolean topos. Here we give a simple example where boundedness is unnecessary.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1985

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]Cole, J. C.. Categories of sets and models of set theory. Ph.D. thesis, University of Sussex, 1972.Google Scholar
[2]Johnstone, P. T.. Quotients of decidable objects in a topos. Math. Proc. Cambridge Philos. Soc. 93, (1983), 409419.CrossRefGoogle Scholar