2 citations · 2 across the 2 of their papers we have counts for
2 papers
math.LO2026
Makkai's lost proof of projectivity of N in the free topos
Henrik Forssell, Peter LeFanu Lumsdaine, Andrew W. Swan
We give a categorical proof of the projectivity of in the free topos -- in proof-theoretic terms, the rule of countable choice for intuitionistic higher-order logic -- based on…
math.LO2026★ 2 cited
Constructive reflectivity principles for regular theories
Henrik Forssell, Peter LeFanu Lumsdaine
Classically, any structure for a signature may be completed to a model of a desired regular theory by means of the chase construction or small object argument. Moreover, t…