exists e
case x.h
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m : ℕ
x✝¹ : n ≤ step m
d : ℕ
h✝ : n + d ≃ step m
motive : ℕ → Prop := fun x => d ≃ x → n ≤ m ∨ n ≃ step m
e : ℕ
x✝ : d ≃ step e
⊢ ∃ k, n + k ≃ m
case x.h
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
order_inst : Order ℕ
n m : ℕ
x✝¹ : n ≤ step m
d : ℕ
h✝ : n + d ≃ step m
motive : ℕ → Prop := fun x => d ≃ x → n ≤ m ∨ n ≃ step m
e : ℕ
x✝ : d ≃ step e
⊢ n + e ≃ m