∀ {C : Type u₁} [inst : CategoryTheory.Category.{v₁, u₁} C] {B A : C} {X : CategoryTheory.Subobject B} {f : A ⟶ B}
  [inst_1 : CategoryTheory.Mono f] (h : X ≤ CategoryTheory.Subobject.mk f),
  CategoryTheory.CategoryStruct.comp (X.ofLEMk f h) f = X.arrow