fact: Definition associator_is_natiso {C : category} {T : tensor_data C} (α : associator_data T) : UU := ∏ (x y z : C), is_z_isomorphism (α x y z).
imports: UniMath.Foundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.Isos