simp
a b : String
n : ℕ
nab : ¬a = b
⊢ Ø ⋁
    ∀ₛ b ;
      (match isTrue (_ : a = a) with
          | isTrue h => fromNat n
          | isFalse h => _ a) +ₛ
          _ b =ₛ
        _ b +ₛ
          match isTrue (_ : a = a) with
          | isTrue h => fromNat n
          | isFalse h => _ a
a b : String
n : ℕ
nab : ¬a = b
⊢ Ø ⋁ ∀ₛ b ; fromNat n +ₛ _ b =ₛ _ b +ₛ fromNat n