have ⟨(_ : m ≤ n₁), (_ : m ≄ n₁)⟩ := lt_defn.mp ‹m < n₁›
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n₁ n₂ m : ℕ
x✝¹ : n₁ ≃ n₂
x✝ : m < n₁
⊢ m < n₂
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n₁ n₂ m : ℕ
x✝¹ : n₁ ≃ n₂
x✝ : m < n₁
left✝ : m ≤ n₁
right✝ : m ≄ n₁
⊢ m < n₂