rw [← i0]
case right.left.inl
A✝ B✝ : Set ℕ
n✝ : ℕ
A B : Set ℕ
hA : 0 ∈ A
hB : 0 ∈ B
α : ℝ := schnirelmannDensity A
halpha : α = schnirelmannDensity A
β : ℝ := schnirelmannDensity B
hbeta : β = schnirelmannDensity B
dum : α * (1 - β) + β = α + β - α * β
n : ℕ
n1 : n > 0
i : ℕ
hi : i ∈ A
x : ℕ
hx : (x ∈ A + B ∧ i < x) ∧ x ∈ A + B ∧ x ≤ next_elm A ⟨i, ⋯⟩ n
i0 : i = 0
⊢ 0 < x
case right.left.inl
A✝ B✝ : Set ℕ
n✝ : ℕ
A B : Set ℕ
hA : 0 ∈ A
hB : 0 ∈ B
α : ℝ := schnirelmannDensity A
halpha : α = schnirelmannDensity A
β : ℝ := schnirelmannDensity B
hbeta : β = schnirelmannDensity B
dum : α * (1 - β) + β = α + β - α * β
n : ℕ
n1 : n > 0
i : ℕ
hi : i ∈ A
x : ℕ
hx : (x ∈ A + B ∧ i < x) ∧ x ∈ A + B ∧ x ≤ next_elm A ⟨i, ⋯⟩ n
i0 : i = 0
⊢ i < x