6 papers · 1 filter
Cellular generation revisited
Sean Cox, Mark Kamsma, Jiří Rosický
Cellular generation, which generalises cofibrant generation, is an important categorical smallness condition on a class of morphisms. A general challenge is to determine whether a…
Cofibrant generation of pure monomorphisms in presheaf categories
Sean Cox, Jonathan Feigert, Mark Kamsma +2
We characterise when the pure monomorphisms in a presheaf category are cofibrantly generated in terms of the category . In particular, when…
Lifting independence along functors
Mark Kamsma, Jiří Rosický
Given a functor and a model-theoretic independence relation on , we can lift that independence relation along to by…
Existentially closed models and locally zero-dimensional toposes
Mark Kamsma, Joshua Wrigley
The notion of an existentially closed model is generalised to a property of geometric morphisms between toposes. We show that important properties of existentially closed models ex…
Classifying toposes for non-geometric theories
Mark Kamsma
The classifying topos of a geometric theory is a topos such that geometric morphisms into it correspond to models of that theory. We study classifying toposes for different infinit…
Unstable independence from the categorical point of view
Mark Kamsma, Jiří Rosický
We give a category-theoretic construction of simple and NSOP-like independence relations in locally finitely presentable categories, and in the more general locally finitely mu…