2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/67886Given 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 figuresCategory TheoryQuantum Algebra18D10, 19D23(primary), 18D50(secondary)text