rw [sum_eq_zero]
case neg
s : SelbergSieve
d : ℕ
h_dvd : ¬d ∣ P
⊢ ν d * 0 = S⁻¹ * ↑(μ d) * ∑ l ∈ P.divisors, if d ∣ l ∧ ↑l ^ 2 ≤ y then g l else 0
case neg
s : SelbergSieve
d : ℕ
h_dvd : ¬d ∣ P
⊢ ν d * 0 = S⁻¹ * ↑(μ d) * 0

case neg
s : SelbergSieve
d : ℕ
h_dvd : ¬d ∣ P
⊢ ∀ x ∈ P.divisors, (if d ∣ x ∧ ↑x ^ 2 ≤ y then g x else 0) = 0