A Counter-Example to Coherence in Cartesian Closed Categories
M. E. Szabo · Canadian Mathematical Bulletin · 1975
It follows from [3] that all morphisms of free closed categories on finite discrete categories are components of natural or “generalized” natural transformations, and from [8] that all hom-sets of such categories are finite. The purpose of this paper is to show that neither statement remains true if the categories are also assumed to be cartesian.