In this blog post, I’ll reformulate Ingo Blechschmidt’s “synthetic quasi-coherence” axiom — or more precisely his “general nullstellensatz” — as a lifting property inspired by Ivan Di Liberti’s work on coherent toposes and ultrastructures. This lifting property shows that synthetic quasi-coherence can be derived from a sort of “directed path induction” for toposes, suggesting the possibility of an internal logic for all toposes in which the axioms for any sort of synthet...
