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Macquarie University  Department of Mathematics

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Categories in Algebra, Geometry and Mathematical Physics

Conference in honour of Ross Street's sixtieth birthday

July 11-16 2005, Macquarie University, Sydney

Mon, 11 July:  14:45 - 15:25

Bi-Heyting toposes and essential covers
Johnstone, Peter (Cambridge University)

Recent work of Francis Borceux and Dominique Bourn has highlighted the
importance of (Grothendieck) toposes in which subobject lattices are
co-Heyting algebras as well as Heyting algebras. Clearly, if a topos admits
an essential surjection from a Boolean topos, then it has this property.
We investigate the extent to which the converse holds.

Typeset PDF of this abstract.