1 citations · 3 across the 4 of their papers we have counts for
4 papers
The representing localic groupoid for a geometric theory
Graham Manuell, Joshua L. Wrigley
We give an expository, and hopefully approachable, account of the Joyal-Tierney result that every topos can be represented as a topos of sheaves on a localic groupoid. We give an e…
Weakly Schreier extensions for general algebras
Graham Manuell, Nelson Martins-Ferreira
Weakly Schreier split extensions are a reasonably large, yet well-understood class of monoid extensions, which generalise some aspects of split extensions of groups. This short not…
Presenting quotient locales
Graham Manuell
It is often useful to be able to deal with locales in terms of presentations of their underlying frames, or equivalently, the geometric theories which they classify. Given a presen…
Monoid extensions and the Grothendieck construction
Graham Manuell
In category theory circles it is well-known that the Schreier theory of group extensions can be understood in terms of the Grothendieck construction on indexed categories. However,…