∀ {L : FirstOrder.Language} {α : Type w} {M : Type w'} {n : ℕ} [inst : L.IsOrdered] [inst_1 : L.Structure M]
  [inst_2 : LE M] [L.OrderedStructure M] {t₁ t₂ : L.Term (α ⊕ Fin n)} {v : α → M} {xs : Fin n → M},
  (t₁.le t₂).Realize v xs =
    (FirstOrder.Language.Term.realize (Sum.elim v xs) t₁ ≤ FirstOrder.Language.Term.realize (Sum.elim v xs) t₂)