∀ {α : Type u_2} {β : Type u_3} {γ : Type u_1} [inst : HeytingAlgebra α] [inst_1 : HeytingAlgebra β]
  [inst_2 : HeytingAlgebra γ] (f : HeytingHom β γ) (g : HeytingHom α β) (a b : α),
  (⇑f ∘ ⇑g) (a ⇨ b) = (⇑f ∘ ⇑g) a ⇨ (⇑f ∘ ⇑g) b