rw [h l (dvd_of_mem_divisors hl) hkl, sum_eq_zero]
case neg
s : SelbergSieve
k n : ℕ
f : ℕ → ℝ
h : ∀ (l : ℕ), l ∣ n → ¬k ∣ l → f l = 0
hn : ¬n = 0
hkn : k ∣ n
l : ℕ
hl : l ∈ n.divisors
hkl : ¬k ∣ l
⊢ f l = ∑ m ∈ n.divisors, if l = k * m then f l else 0
case neg
s : SelbergSieve
k n : ℕ
f : ℕ → ℝ
h : ∀ (l : ℕ), l ∣ n → ¬k ∣ l → f l = 0
hn : ¬n = 0
hkn : k ∣ n
l : ℕ
hl : l ∈ n.divisors
hkl : ¬k ∣ l
⊢ ∀ x ∈ n.divisors, (if l = k * x then 0 else 0) = 0