Joshua Wrigley - The Logic and Geometry of Localic Morphisms
Channel: Institut des Hautes Études Scientifiques (IHÉS)
Date: 2021-07-01

Talk at the school and conference “Toposes online” (24-30 June 2021):
https://aroundtoposes.com/toposesonline/

Slides:
https://aroundtoposes.com/wp-content/uploads/2021/07/WrigleySlidesToposesOnline.pdf

In this presentation, a substitutive syntactic site for the classifying topos of a geometric theory is introduced. This construction is understood in light of the relationship between localic expansions and internal locales. The usual syntactic site is recovered as a topos theoretic completion of the substitutive site.