fact: Definition runitor_transf (a b : C) : bindelta_pair_functor (functor_identity (hom a b)) (constant_functor (hom a b) (hom b b) (identity b)) ∙ hcomp_functor ⟹ functor_identity (hom a b).
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