unfold.lean:10:2: proof state
a b : ℕ,
h : a + b = 0
⊢ f b a = 0
unfold.lean:12:2: proof state
a b : ℕ,
h : a + b = 0
⊢ b + a = 0
unfold.lean:21:2: proof state
a b : ℕ,
h : a + b = 0
⊢ b + a = 0
unfold.lean:30:2: proof state
a b c : ℕ,
h₁ : c + c = 0,
h₂ : a + b = 0
⊢ f b a = f c c
unfold.lean:39:2: proof state
a b c : ℕ,
h₁ : c + c = 0,
h₂ : a + b = 0
⊢ f b a = f c c