Braided Premonoidal Coherence
arXiv:math/0306371
Abstract
Given a category with a bifunctor and natural isomorphisms for associativity, commutativity and left and right identity we do not assume that extra constraining diagrams hold. We introduce groupoids of coupling trees to describe a version of coherence that is weaker than the usual notion of monoidal coherence.
28 pages, 7 figures