Coherence for Skew-Nearsemiring categories

UUSTALU, TARMO; RIVAS, EXEQUIEL; JASKELIOFF, MAURO; VELTRI, NICCÒLO

Workshop; Higher-Dimensional Rewriting and Applications; 2017

  We consider skew near-semiring categories, a relaxation of  near-semiring categories where the unitors, associators, absorber  and distributor are not required to be natural isomorphisms, they  are just natural transformations in a particular direction. We  prove a coherence theorem for such categories. The theorem states  that, in a free skew near-semiring category over a set of objects,  any two maps between an object and an object in normal form are  equal.