apply this
case h
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
n : ℕ
x✝ : Positive 0
this : 0 ≄ 0
⊢ False
case h
ℕ : Type
inst✝³ : Core ℕ
inst✝² : Induction ℕ
inst✝¹ : Addition ℕ
inst✝ : Sign ℕ
n : ℕ
x✝ : Positive 0
this : 0 ≄ 0
⊢ 0 ≃ 0