exact AA.inject ‹step (n₁ + d) ≃ step n₂›
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n₁ n₂ : ℕ
x✝ : step n₁ ≤ step n₂
d : ℕ
h✝ : step n₁ + d ≃ step n₂
this : step (n₁ + d) ≃ step n₂
⊢ n₁ + d ≃ n₂
no goals