exact AA.cancelL ‹n + (m₁ + d) ≃ n + m₂›
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m₁ m₂ : ℕ
x✝ : n + m₁ ≤ n + m₂
d : ℕ
h✝ : n + m₁ + d ≃ n + m₂
this : n + (m₁ + d) ≃ n + m₂
⊢ m₁ + d ≃ m₂
no goals