Relational Semigroups and Object-Free Categories
James Cranch, Simon Doherty, Georg Struth · arXiv (Cornell University) · 2020
This note relates axioms for partial semigroups and monoids with those for small object-free categories, either with multiple monoidal units or with source and target maps. We discuss the adjunction of a zero element to both kinds of category and provide examples that separate the algebras considered.