fact: Definition vassocl {a b : C} {f g h k : C⟦a, b⟧} (x : f ==> g) (y : g ==> h) (z : h ==> k) : (x • y) • z = x • (y • z) := !vassocr x y z.
imports: UniMath.Tactics.EnsureStructuredProofs UniMath.Foundations.All UniMath.MoreFoundations.All UniMath.CategoryTheory.Core.Categories UniMath.CategoryTheory.Core.Isos UniMath.CategoryTheory.Core.Functors UniMath.CategoryTheory.Core.NaturalTransformations UniMath.CategoryTheory.PrecategoryBinProduct