∀ {α : Type u_2} {β : Type u_3} {γ : Type u_4} {δ : Type u_5} [inst : HeytingAlgebra α] [inst_1 : HeytingAlgebra β]
  [inst_2 : HeytingAlgebra γ] [inst_3 : HeytingAlgebra δ] (f : HeytingHom γ δ) (g : HeytingHom β γ)
  (h : HeytingHom α β), (f.comp g).comp h = f.comp (g.comp h)